Merge branch 'j6t/mingw'

* j6t/mingw: (38 commits)
  compat/pread.c: Add a forward declaration to fix a warning
  Windows: Fix ntohl() related warnings about printf formatting
  Windows: TMP and TEMP environment variables specify a temporary directory.
  Windows: Make 'git help -a' work.
  Windows: Work around an oddity when a pipe with no reader is written to.
  Windows: Make the pager work.
  When installing, be prepared that template_dir may be relative.
  Windows: Use a relative default template_dir and ETC_GITCONFIG
  Windows: Compute the fallback for exec_path from the program invocation.
  Turn builtin_exec_path into a function.
  Windows: Use a customized struct stat that also has the st_blocks member.
  Windows: Add a custom implementation for utime().
  Windows: Add a new lstat and fstat implementation based on Win32 API.
  Windows: Implement a custom spawnve().
  Windows: Implement wrappers for gethostbyname(), socket(), and connect().
  Windows: Work around incompatible sort and find.
  Windows: Implement asynchronous functions as threads.
  Windows: Disambiguate DOS style paths from SSH URLs.
  Windows: A rudimentary poll() emulation.
  Windows: Implement start_command().
  ...

26 files changed, 7633 insertions, 80 deletions

diff --git a/Documentation/git.txt b/Documentation/git.txt
index 57a3a84be..22702c260 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -410,9 +410,9 @@ git so take care if using Cogito etc.
 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 	Due to the immutable nature of git objects, old objects can be
 	archived into shared, read-only directories. This variable
-	specifies a ":" separated list of git object directories which
-	can be used to search for git objects. New objects will not be
-	written to these directories.
+	specifies a ":" separated (on Windows ";" separated) list
+	of git object directories which can be used to search for git
+	objects. New objects will not be written to these directories.
 
 'GIT_DIR'::
 	If the 'GIT_DIR' environment variable is set then it
diff --git a/Makefile b/Makefile
index ba16f2679..78e08d374 100644
--- a/Makefile
+++ b/Makefile
@@ -205,7 +205,7 @@ GITWEB_FAVICON = git-favicon.png
 GITWEB_SITE_HEADER =
 GITWEB_SITE_FOOTER =
 
-export prefix bindir gitexecdir sharedir template_dir htmldir sysconfdir
+export prefix bindir gitexecdir sharedir htmldir sysconfdir
 
 CC = gcc
 AR = ar
@@ -273,11 +273,9 @@ EXTRA_PROGRAMS =
 
 # ... and all the rest that could be moved out of bindir to gitexecdir
 PROGRAMS += $(EXTRA_PROGRAMS)
-PROGRAMS += git-daemon$X
 PROGRAMS += git-fast-import$X
 PROGRAMS += git-fetch-pack$X
 PROGRAMS += git-hash-object$X
-PROGRAMS += git-imap-send$X
 PROGRAMS += git-index-pack$X
 PROGRAMS += git-merge-index$X
 PROGRAMS += git-merge-tree$X
@@ -337,6 +335,7 @@ LIB_H += builtin.h
 LIB_H += cache.h
 LIB_H += cache-tree.h
 LIB_H += commit.h
+LIB_H += compat/mingw.h
 LIB_H += csum-file.h
 LIB_H += decorate.h
 LIB_H += delta.h
@@ -717,6 +716,36 @@ ifeq ($(uname_S),HP-UX)
 	NO_HSTRERROR = YesPlease
 	NO_SYS_SELECT_H = YesPlease
 endif
+ifneq (,$(findstring MINGW,$(uname_S)))
+	NO_MMAP = YesPlease
+	NO_PREAD = YesPlease
+	NO_OPENSSL = YesPlease
+	NO_CURL = YesPlease
+	NO_SYMLINK_HEAD = YesPlease
+	NO_IPV6 = YesPlease
+	NO_SETENV = YesPlease
+	NO_UNSETENV = YesPlease
+	NO_STRCASESTR = YesPlease
+	NO_STRLCPY = YesPlease
+	NO_MEMMEM = YesPlease
+	NEEDS_LIBICONV = YesPlease
+	OLD_ICONV = YesPlease
+	NO_C99_FORMAT = YesPlease
+	NO_STRTOUMAX = YesPlease
+	NO_MKDTEMP = YesPlease
+	SNPRINTF_RETURNS_BOGUS = YesPlease
+	NO_SVN_TESTS = YesPlease
+	NO_PERL_MAKEMAKER = YesPlease
+	NO_POSIX_ONLY_PROGRAMS = YesPlease
+	COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat
+	COMPAT_CFLAGS += -DSNPRINTF_SIZE_CORR=1
+	COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"
+	COMPAT_OBJS += compat/mingw.o compat/fnmatch.o compat/regex.o
+	EXTLIBS += -lws2_32
+	X = .exe
+	template_dir = ../share/git-core/templates/
+	ETC_GITCONFIG = ../etc/gitconfig
+endif
 ifneq (,$(findstring arm,$(uname_M)))
 	ARM_SHA1 = YesPlease
 endif
@@ -777,6 +806,10 @@ ifdef ZLIB_PATH
 endif
 EXTLIBS += -lz
 
+ifndef NO_POSIX_ONLY_PROGRAMS
+	PROGRAMS += git-daemon$X
+	PROGRAMS += git-imap-send$X
+endif
 ifndef NO_OPENSSL
 	OPENSSL_LIBSSL = -lssl
 	ifdef OPENSSLDIR
@@ -1268,6 +1301,13 @@ remove-dashes:
 
 ### Installation rules
 
+ifeq ($(firstword $(subst /, ,$(template_dir))),..)
+template_instdir = $(gitexecdir)/$(template_dir)
+else
+template_instdir = $(template_dir)
+endif
+export template_instdir
+
 install: all
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(bindir_SQ)'
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(gitexecdir_SQ)'
diff --git a/cache.h b/cache.h
index 188428dd2..35a91320a 100644
--- a/cache.h
+++ b/cache.h
@@ -522,7 +522,7 @@ int safe_create_leading_directories_const(const char *path);
 char *enter_repo(char *path, int strict);
 static inline int is_absolute_path(const char *path)
 {
-	return path[0] == '/';
+	return path[0] == '/' || has_dos_drive_prefix(path);
 }
 const char *make_absolute_path(const char *path);
 const char *make_nonrelative_path(const char *path);
diff --git a/compat/fnmatch.c b/compat/fnmatch.c
new file mode 100644
index 000000000..1f4ead5f9
--- /dev/null
+++ b/compat/fnmatch.c
@@ -0,0 +1,488 @@
+/* Copyright (C) 1991, 92, 93, 96, 97, 98, 99 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with this library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+/* Enable GNU extensions in fnmatch.h.  */
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE	1
+#endif
+
+#include <errno.h>
+#include <fnmatch.h>
+#include <ctype.h>
+
+#if HAVE_STRING_H || defined _LIBC
+# include <string.h>
+#else
+# include <strings.h>
+#endif
+
+#if defined STDC_HEADERS || defined _LIBC
+# include <stdlib.h>
+#endif
+
+/* For platform which support the ISO C amendement 1 functionality we
+   support user defined character classes.  */
+#if defined _LIBC || (defined HAVE_WCTYPE_H && defined HAVE_WCHAR_H)
+/* Solaris 2.5 has a bug: <wchar.h> must be included before <wctype.h>.  */
+# include <wchar.h>
+# include <wctype.h>
+#endif
+
+/* Comment out all this code if we are using the GNU C Library, and are not
+   actually compiling the library itself.  This code is part of the GNU C
+   Library, but also included in many other GNU distributions.  Compiling
+   and linking in this code is a waste when using the GNU C library
+   (especially if it is a shared library).  Rather than having every GNU
+   program understand `configure --with-gnu-libc' and omit the object files,
+   it is simpler to just do this in the source for each such file.  */
+
+#if defined _LIBC || !defined __GNU_LIBRARY__
+
+
+# if defined STDC_HEADERS || !defined isascii
+#  define ISASCII(c) 1
+# else
+#  define ISASCII(c) isascii(c)
+# endif
+
+# ifdef isblank
+#  define ISBLANK(c) (ISASCII (c) && isblank (c))
+# else
+#  define ISBLANK(c) ((c) == ' ' || (c) == '\t')
+# endif
+# ifdef isgraph
+#  define ISGRAPH(c) (ISASCII (c) && isgraph (c))
+# else
+#  define ISGRAPH(c) (ISASCII (c) && isprint (c) && !isspace (c))
+# endif
+
+# define ISPRINT(c) (ISASCII (c) && isprint (c))
+# define ISDIGIT(c) (ISASCII (c) && isdigit (c))
+# define ISALNUM(c) (ISASCII (c) && isalnum (c))
+# define ISALPHA(c) (ISASCII (c) && isalpha (c))
+# define ISCNTRL(c) (ISASCII (c) && iscntrl (c))
+# define ISLOWER(c) (ISASCII (c) && islower (c))
+# define ISPUNCT(c) (ISASCII (c) && ispunct (c))
+# define ISSPACE(c) (ISASCII (c) && isspace (c))
+# define ISUPPER(c) (ISASCII (c) && isupper (c))
+# define ISXDIGIT(c) (ISASCII (c) && isxdigit (c))
+
+# define STREQ(s1, s2) ((strcmp (s1, s2) == 0))
+
+# if defined _LIBC || (defined HAVE_WCTYPE_H && defined HAVE_WCHAR_H)
+/* The GNU C library provides support for user-defined character classes
+   and the functions from ISO C amendement 1.  */
+#  ifdef CHARCLASS_NAME_MAX
+#   define CHAR_CLASS_MAX_LENGTH CHARCLASS_NAME_MAX
+#  else
+/* This shouldn't happen but some implementation might still have this
+   problem.  Use a reasonable default value.  */
+#   define CHAR_CLASS_MAX_LENGTH 256
+#  endif
+
+#  ifdef _LIBC
+#   define IS_CHAR_CLASS(string) __wctype (string)
+#  else
+#   define IS_CHAR_CLASS(string) wctype (string)
+#  endif
+# else
+#  define CHAR_CLASS_MAX_LENGTH  6 /* Namely, `xdigit'.  */
+
+#  define IS_CHAR_CLASS(string)						      \
+   (STREQ (string, "alpha") || STREQ (string, "upper")			      \
+    || STREQ (string, "lower") || STREQ (string, "digit")		      \
+    || STREQ (string, "alnum") || STREQ (string, "xdigit")		      \
+    || STREQ (string, "space") || STREQ (string, "print")		      \
+    || STREQ (string, "punct") || STREQ (string, "graph")		      \
+    || STREQ (string, "cntrl") || STREQ (string, "blank"))
+# endif
+
+/* Avoid depending on library functions or files
+   whose names are inconsistent.  */
+
+# if !defined _LIBC && !defined getenv
+extern char *getenv ();
+# endif
+
+# ifndef errno
+extern int errno;
+# endif
+
+/* This function doesn't exist on most systems.  */
+
+# if !defined HAVE___STRCHRNUL && !defined _LIBC
+static char *
+__strchrnul (s, c)
+     const char *s;
+     int c;
+{
+  char *result = strchr (s, c);
+  if (result == NULL)
+    result = strchr (s, '\0');
+  return result;
+}
+# endif
+
+# ifndef internal_function
+/* Inside GNU libc we mark some function in a special way.  In other
+   environments simply ignore the marking.  */
+#  define internal_function
+# endif
+
+/* Match STRING against the filename pattern PATTERN, returning zero if
+   it matches, nonzero if not.  */
+static int internal_fnmatch __P ((const char *pattern, const char *string,
+				  int no_leading_period, int flags))
+     internal_function;
+static int
+internal_function
+internal_fnmatch (pattern, string, no_leading_period, flags)
+     const char *pattern;
+     const char *string;
+     int no_leading_period;
+     int flags;
+{
+  register const char *p = pattern, *n = string;
+  register unsigned char c;
+
+/* Note that this evaluates C many times.  */
+# ifdef _LIBC
+#  define FOLD(c) ((flags & FNM_CASEFOLD) ? tolower (c) : (c))
+# else
+#  define FOLD(c) ((flags & FNM_CASEFOLD) && ISUPPER (c) ? tolower (c) : (c))
+# endif
+
+  while ((c = *p++) != '\0')
+    {
+      c = FOLD (c);
+
+      switch (c)
+	{
+	case '?':
+	  if (*n == '\0')
+	    return FNM_NOMATCH;
+	  else if (*n == '/' && (flags & FNM_FILE_NAME))
+	    return FNM_NOMATCH;
+	  else if (*n == '.' && no_leading_period
+		   && (n == string
+		       || (n[-1] == '/' && (flags & FNM_FILE_NAME))))
+	    return FNM_NOMATCH;
+	  break;
+
+	case '\\':
+	  if (!(flags & FNM_NOESCAPE))
+	    {
+	      c = *p++;
+	      if (c == '\0')
+		/* Trailing \ loses.  */
+		return FNM_NOMATCH;
+	      c = FOLD (c);
+	    }
+	  if (FOLD ((unsigned char) *n) != c)
+	    return FNM_NOMATCH;
+	  break;
+
+	case '*':
+	  if (*n == '.' && no_leading_period
+	      && (n == string
+		  || (n[-1] == '/' && (flags & FNM_FILE_NAME))))
+	    return FNM_NOMATCH;
+
+	  for (c = *p++; c == '?' || c == '*'; c = *p++)
+	    {
+	      if (*n == '/' && (flags & FNM_FILE_NAME))
+		/* A slash does not match a wildcard under FNM_FILE_NAME.  */
+		return FNM_NOMATCH;
+	      else if (c == '?')
+		{
+		  /* A ? needs to match one character.  */
+		  if (*n == '\0')
+		    /* There isn't another character; no match.  */
+		    return FNM_NOMATCH;
+		  else
+		    /* One character of the string is consumed in matching
+		       this ? wildcard, so *??? won't match if there are
+		       less than three characters.  */
+		    ++n;
+		}
+	    }
+
+	  if (c == '\0')
+	    /* The wildcard(s) is/are the last element of the pattern.
+	       If the name is a file name and contains another slash
+	       this does mean it cannot match.  */
+	    return ((flags & FNM_FILE_NAME) && strchr (n, '/') != NULL
+		    ? FNM_NOMATCH : 0);
+	  else
+	    {
+	      const char *endp;
+
+	      endp = __strchrnul (n, (flags & FNM_FILE_NAME) ? '/' : '\0');
+
+	      if (c == '[')
+		{
+		  int flags2 = ((flags & FNM_FILE_NAME)
+				? flags : (flags & ~FNM_PERIOD));
+
+		  for (--p; n < endp; ++n)
+		    if (internal_fnmatch (p, n,
+					  (no_leading_period
+					   && (n == string
+					       || (n[-1] == '/'
+						   && (flags
+						       & FNM_FILE_NAME)))),
+					  flags2)
+			== 0)
+		      return 0;
+		}
+	      else if (c == '/' && (flags & FNM_FILE_NAME))
+		{
+		  while (*n != '\0' && *n != '/')
+		    ++n;
+		  if (*n == '/'
+		      && (internal_fnmatch (p, n + 1, flags & FNM_PERIOD,
+					    flags) == 0))
+		    return 0;
+		}
+	      else
+		{
+		  int flags2 = ((flags & FNM_FILE_NAME)
+				? flags : (flags & ~FNM_PERIOD));
+
+		  if (c == '\\' && !(flags & FNM_NOESCAPE))
+		    c = *p;
+		  c = FOLD (c);
+		  for (--p; n < endp; ++n)
+		    if (FOLD ((unsigned char) *n) == c
+			&& (internal_fnmatch (p, n,
+					      (no_leading_period
+					       && (n == string
+						   || (n[-1] == '/'
+						       && (flags
+							   & FNM_FILE_NAME)))),
+					      flags2) == 0))
+		      return 0;
+		}
+	    }
+
+	  /* If we come here no match is possible with the wildcard.  */
+	  return FNM_NOMATCH;
+
+	case '[':
+	  {
+	    /* Nonzero if the sense of the character class is inverted.  */
+	    static int posixly_correct;
+	    register int not;
+	    char cold;
+
+	    if (posixly_correct == 0)
+	      posixly_correct = getenv ("POSIXLY_CORRECT") != NULL ? 1 : -1;
+
+	    if (*n == '\0')
+	      return FNM_NOMATCH;
+
+	    if (*n == '.' && no_leading_period && (n == string
+						   || (n[-1] == '/'
+						       && (flags
+							   & FNM_FILE_NAME))))
+	      return FNM_NOMATCH;
+
+	    if (*n == '/' && (flags & FNM_FILE_NAME))
+	      /* `/' cannot be matched.  */
+	      return FNM_NOMATCH;
+
+	    not = (*p == '!' || (posixly_correct < 0 && *p == '^'));
+	    if (not)
+	      ++p;
+
+	    c = *p++;
+	    for (;;)
+	      {
+		unsigned char fn = FOLD ((unsigned char) *n);
+
+		if (!(flags & FNM_NOESCAPE) && c == '\\')
+		  {
+		    if (*p == '\0')
+		      return FNM_NOMATCH;
+		    c = FOLD ((unsigned char) *p);
+		    ++p;
+
+		    if (c == fn)
+		      goto matched;
+		  }
+		else if (c == '[' && *p == ':')
+		  {
+		    /* Leave room for the null.  */
+		    char str[CHAR_CLASS_MAX_LENGTH + 1];
+		    size_t c1 = 0;
+# if defined _LIBC || (defined HAVE_WCTYPE_H && defined HAVE_WCHAR_H)
+		    wctype_t wt;
+# endif
+		    const char *startp = p;
+
+		    for (;;)
+		      {
+			if (c1 == CHAR_CLASS_MAX_LENGTH)
+			  /* The name is too long and therefore the pattern
+			     is ill-formed.  */
+			  return FNM_NOMATCH;
+
+			c = *++p;
+			if (c == ':' && p[1] == ']')
+			  {
+			    p += 2;
+			    break;
+			  }
+			if (c < 'a' || c >= 'z')
+			  {
+			    /* This cannot possibly be a character class name.
+			       Match it as a normal range.  */
+			    p = startp;
+			    c = '[';
+			    goto normal_bracket;
+			  }
+			str[c1++] = c;
+		      }
+		    str[c1] = '\0';
+
+# if defined _LIBC || (defined HAVE_WCTYPE_H && defined HAVE_WCHAR_H)
+		    wt = IS_CHAR_CLASS (str);
+		    if (wt == 0)
+		      /* Invalid character class name.  */
+		      return FNM_NOMATCH;
+
+		    if (__iswctype (__btowc ((unsigned char) *n), wt))
+		      goto matched;
+# else
+		    if ((STREQ (str, "alnum") && ISALNUM ((unsigned char) *n))
+			|| (STREQ (str, "alpha") && ISALPHA ((unsigned char) *n))
+			|| (STREQ (str, "blank") && ISBLANK ((unsigned char) *n))
+			|| (STREQ (str, "cntrl") && ISCNTRL ((unsigned char) *n))
+			|| (STREQ (str, "digit") && ISDIGIT ((unsigned char) *n))
+			|| (STREQ (str, "graph") && ISGRAPH ((unsigned char) *n))
+			|| (STREQ (str, "lower") && ISLOWER ((unsigned char) *n))
+			|| (STREQ (str, "print") && ISPRINT ((unsigned char) *n))
+			|| (STREQ (str, "punct") && ISPUNCT ((unsigned char) *n))
+			|| (STREQ (str, "space") && ISSPACE ((unsigned char) *n))
+			|| (STREQ (str, "upper") && ISUPPER ((unsigned char) *n))
+			|| (STREQ (str, "xdigit") && ISXDIGIT ((unsigned char) *n)))
+		      goto matched;
+# endif
+		  }
+		else if (c == '\0')
+		  /* [ (unterminated) loses.  */
+		  return FNM_NOMATCH;
+		else
+		  {
+		  normal_bracket:
+		    if (FOLD (c) == fn)
+		      goto matched;
+
+		    cold = c;
+		    c = *p++;
+
+		    if (c == '-' && *p != ']')
+		      {
+			/* It is a range.  */
+			unsigned char cend = *p++;
+			if (!(flags & FNM_NOESCAPE) && cend == '\\')
+			  cend = *p++;
+			if (cend == '\0')
+			  return FNM_NOMATCH;
+
+			if (cold <= fn && fn <= FOLD (cend))
+			  goto matched;
+
+			c = *p++;
+		      }
+		  }
+
+		if (c == ']')
+		  break;
+	      }
+
+	    if (!not)
+	      return FNM_NOMATCH;
+	    break;
+
+	  matched:
+	    /* Skip the rest of the [...] that already matched.  */
+	    while (c != ']')
+	      {
+		if (c == '\0')
+		  /* [... (unterminated) loses.  */
+		  return FNM_NOMATCH;
+
+		c = *p++;
+		if (!(flags & FNM_NOESCAPE) && c == '\\')
+		  {
+		    if (*p == '\0')
+		      return FNM_NOMATCH;
+		    /* XXX 1003.2d11 is unclear if this is right.  */
+		    ++p;
+		  }
+		else if (c == '[' && *p == ':')
+		  {
+		    do
+		      if (*++p == '\0')
+			return FNM_NOMATCH;
+		    while (*p != ':' || p[1] == ']');
+		    p += 2;
+		    c = *p;
+		  }
+	      }
+	    if (not)
+	      return FNM_NOMATCH;
+	  }
+	  break;
+
+	default:
+	  if (c != FOLD ((unsigned char) *n))
+	    return FNM_NOMATCH;
+	}
+
+      ++n;
+    }
+
+  if (*n == '\0')
+    return 0;
+
+  if ((flags & FNM_LEADING_DIR) && *n == '/')
+    /* The FNM_LEADING_DIR flag says that "foo*" matches "foobar/frobozz".  */
+    return 0;
+
+  return FNM_NOMATCH;
+
+# undef FOLD
+}
+
+
+int
+fnmatch (pattern, string, flags)
+     const char *pattern;
+     const char *string;
+     int flags;
+{
+  return internal_fnmatch (pattern, string, flags & FNM_PERIOD, flags);
+}
+
+#endif	/* _LIBC or not __GNU_LIBRARY__.  */
diff --git a/compat/fnmatch.h b/compat/fnmatch.h
new file mode 100644
index 000000000..cc3ec3794
--- /dev/null
+++ b/compat/fnmatch.h
@@ -0,0 +1,84 @@
+/* Copyright (C) 1991, 92, 93, 96, 97, 98, 99 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#ifndef	_FNMATCH_H
+#define	_FNMATCH_H	1
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+#if defined __cplusplus || (defined __STDC__ && __STDC__) || defined WINDOWS32
+# if !defined __GLIBC__ || !defined __P
+#  undef	__P
+#  define __P(protos)	protos
+# endif
+#else /* Not C++ or ANSI C.  */
+# undef	__P
+# define __P(protos)	()
+/* We can get away without defining `const' here only because in this file
+   it is used only inside the prototype for `fnmatch', which is elided in
+   non-ANSI C where `const' is problematical.  */
+#endif /* C++ or ANSI C.  */
+
+#ifndef const
+# if (defined __STDC__ && __STDC__) || defined __cplusplus
+#  define __const	const
+# else
+#  define __const
+# endif
+#endif
+
+/* We #undef these before defining them because some losing systems
+   (HP-UX A.08.07 for example) define these in <unistd.h>.  */
+#undef	FNM_PATHNAME
+#undef	FNM_NOESCAPE
+#undef	FNM_PERIOD
+
+/* Bits set in the FLAGS argument to `fnmatch'.  */
+#define	FNM_PATHNAME	(1 << 0) /* No wildcard can ever match `/'.  */
+#define	FNM_NOESCAPE	(1 << 1) /* Backslashes don't quote special chars.  */
+#define	FNM_PERIOD	(1 << 2) /* Leading `.' is matched only explicitly.  */
+
+#if !defined _POSIX_C_SOURCE || _POSIX_C_SOURCE < 2 || defined _GNU_SOURCE
+# define FNM_FILE_NAME	 FNM_PATHNAME	/* Preferred GNU name.  */
+# define FNM_LEADING_DIR (1 << 3)	/* Ignore `/...' after a match.  */
+# define FNM_CASEFOLD	 (1 << 4)	/* Compare without regard to case.  */
+#endif
+
+/* Value returned by `fnmatch' if STRING does not match PATTERN.  */
+#define	FNM_NOMATCH	1
+
+/* This value is returned if the implementation does not support
+   `fnmatch'.  Since this is not the case here it will never be
+   returned but the conformance test suites still require the symbol
+   to be defined.  */
+#ifdef _XOPEN_SOURCE
+# define FNM_NOSYS	(-1)
+#endif
+
+/* Match NAME against the filename pattern PATTERN,
+   returning zero if it matches, FNM_NOMATCH if not.  */
+extern int fnmatch __P ((__const char *__pattern, __const char *__name,
+			 int __flags));
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif /* fnmatch.h */
diff --git a/compat/mingw.c b/compat/mingw.c
new file mode 100644
index 000000000..3a05fe7da
--- /dev/null
+++ b/compat/mingw.c
@@ -0,0 +1,1019 @@
+#include "../git-compat-util.h"
+#include "../strbuf.h"
+
+unsigned int _CRT_fmode = _O_BINARY;
+
+#undef open
+int mingw_open (const char *filename, int oflags, ...)
+{
+	va_list args;
+	unsigned mode;
+	va_start(args, oflags);
+	mode = va_arg(args, int);
+	va_end(args);
+
+	if (!strcmp(filename, "/dev/null"))
+		filename = "nul";
+	int fd = open(filename, oflags, mode);
+	if (fd < 0 && (oflags & O_CREAT) && errno == EACCES) {
+		DWORD attrs = GetFileAttributes(filename);
+		if (attrs != INVALID_FILE_ATTRIBUTES && (attrs & FILE_ATTRIBUTE_DIRECTORY))
+			errno = EISDIR;
+	}
+	return fd;
+}
+
+static inline time_t filetime_to_time_t(const FILETIME *ft)
+{
+	long long winTime = ((long long)ft->dwHighDateTime << 32) + ft->dwLowDateTime;
+	winTime -= 116444736000000000LL; /* Windows to Unix Epoch conversion */
+	winTime /= 10000000;		 /* Nano to seconds resolution */
+	return (time_t)winTime;
+}
+
+static inline size_t size_to_blocks(size_t s)
+{
+	return (s+511)/512;
+}
+
+extern int _getdrive( void );
+/* We keep the do_lstat code in a separate function to avoid recursion.
+ * When a path ends with a slash, the stat will fail with ENOENT. In
+ * this case, we strip the trailing slashes and stat again.
+ */
+static int do_lstat(const char *file_name, struct stat *buf)
+{
+	WIN32_FILE_ATTRIBUTE_DATA fdata;
+
+	if (GetFileAttributesExA(file_name, GetFileExInfoStandard, &fdata)) {
+		int fMode = S_IREAD;
+		if (fdata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
+			fMode |= S_IFDIR;
+		else
+			fMode |= S_IFREG;
+		if (!(fdata.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
+			fMode |= S_IWRITE;
+
+		buf->st_ino = 0;
+		buf->st_gid = 0;
+		buf->st_uid = 0;
+		buf->st_mode = fMode;
+		buf->st_size = fdata.nFileSizeLow; /* Can't use nFileSizeHigh, since it's not a stat64 */
+		buf->st_blocks = size_to_blocks(buf->st_size);
+		buf->st_dev = _getdrive() - 1;
+		buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
+		buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
+		buf->st_ctime = filetime_to_time_t(&(fdata.ftCreationTime));
+		errno = 0;
+		return 0;
+	}
+
+	switch (GetLastError()) {
+	case ERROR_ACCESS_DENIED:
+	case ERROR_SHARING_VIOLATION:
+	case ERROR_LOCK_VIOLATION:
+	case ERROR_SHARING_BUFFER_EXCEEDED:
+		errno = EACCES;
+		break;
+	case ERROR_BUFFER_OVERFLOW:
+		errno = ENAMETOOLONG;
+		break;
+	case ERROR_NOT_ENOUGH_MEMORY:
+		errno = ENOMEM;
+		break;
+	default:
+		errno = ENOENT;
+		break;
+	}
+	return -1;
+}
+
+/* We provide our own lstat/fstat functions, since the provided
+ * lstat/fstat functions are so slow. These stat functions are
+ * tailored for Git's usage (read: fast), and are not meant to be
+ * complete. Note that Git stat()s are redirected to mingw_lstat()
+ * too, since Windows doesn't really handle symlinks that well.
+ */
+int mingw_lstat(const char *file_name, struct mingw_stat *buf)
+{
+	int namelen;
+	static char alt_name[PATH_MAX];
+
+	if (!do_lstat(file_name, buf))
+		return 0;
+
+	/* if file_name ended in a '/', Windows returned ENOENT;
+	 * try again without trailing slashes
+	 */
+	if (errno != ENOENT)
+		return -1;
+
+	namelen = strlen(file_name);
+	if (namelen && file_name[namelen-1] != '/')
+		return -1;
+	while (namelen && file_name[namelen-1] == '/')
+		--namelen;
+	if (!namelen || namelen >= PATH_MAX)
+		return -1;
+
+	memcpy(alt_name, file_name, namelen);
+	alt_name[namelen] = 0;
+	return do_lstat(alt_name, buf);
+}
+
+#undef fstat
+#undef stat
+int mingw_fstat(int fd, struct mingw_stat *buf)
+{
+	HANDLE fh = (HANDLE)_get_osfhandle(fd);
+	BY_HANDLE_FILE_INFORMATION fdata;
+
+	if (fh == INVALID_HANDLE_VALUE) {
+		errno = EBADF;
+		return -1;
+	}
+	/* direct non-file handles to MS's fstat() */
+	if (GetFileType(fh) != FILE_TYPE_DISK) {
+		struct stat st;
+		if (fstat(fd, &st))
+			return -1;
+		buf->st_ino = st.st_ino;
+		buf->st_gid = st.st_gid;
+		buf->st_uid = st.st_uid;
+		buf->st_mode = st.st_mode;
+		buf->st_size = st.st_size;
+		buf->st_blocks = size_to_blocks(buf->st_size);
+		buf->st_dev = st.st_dev;
+		buf->st_atime = st.st_atime;
+		buf->st_mtime = st.st_mtime;
+		buf->st_ctime = st.st_ctime;
+		return 0;
+	}
+
+	if (GetFileInformationByHandle(fh, &fdata)) {
+		int fMode = S_IREAD;
+		if (fdata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
+			fMode |= S_IFDIR;
+		else
+			fMode |= S_IFREG;
+		if (!(fdata.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
+			fMode |= S_IWRITE;
+
+		buf->st_ino = 0;
+		buf->st_gid = 0;
+		buf->st_uid = 0;
+		buf->st_mode = fMode;
+		buf->st_size = fdata.nFileSizeLow; /* Can't use nFileSizeHigh, since it's not a stat64 */
+		buf->st_blocks = size_to_blocks(buf->st_size);
+		buf->st_dev = _getdrive() - 1;
+		buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
+		buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
+		buf->st_ctime = filetime_to_time_t(&(fdata.ftCreationTime));
+		return 0;
+	}
+	errno = EBADF;
+	return -1;
+}
+
+static inline void time_t_to_filetime(time_t t, FILETIME *ft)
+{
+	long long winTime = t * 10000000LL + 116444736000000000LL;
+	ft->dwLowDateTime = winTime;
+	ft->dwHighDateTime = winTime >> 32;
+}
+
+int mingw_utime (const char *file_name, const struct utimbuf *times)
+{
+	FILETIME mft, aft;
+	int fh, rc;
+
+	/* must have write permission */
+	if ((fh = open(file_name, O_RDWR | O_BINARY)) < 0)
+		return -1;
+
+	time_t_to_filetime(times->modtime, &mft);
+	time_t_to_filetime(times->actime, &aft);
+	if (!SetFileTime((HANDLE)_get_osfhandle(fh), NULL, &aft, &mft)) {
+		errno = EINVAL;
+		rc = -1;
+	} else
+		rc = 0;
+	close(fh);
+	return rc;
+}
+
+unsigned int sleep (unsigned int seconds)
+{
+	Sleep(seconds*1000);
+	return 0;
+}
+
+int mkstemp(char *template)
+{
+	char *filename = mktemp(template);
+	if (filename == NULL)
+		return -1;
+	return open(filename, O_RDWR | O_CREAT, 0600);
+}
+
+int gettimeofday(struct timeval *tv, void *tz)
+{
+	SYSTEMTIME st;
+	struct tm tm;
+	GetSystemTime(&st);
+	tm.tm_year = st.wYear-1900;
+	tm.tm_mon = st.wMonth-1;
+	tm.tm_mday = st.wDay;
+	tm.tm_hour = st.wHour;
+	tm.tm_min = st.wMinute;
+	tm.tm_sec = st.wSecond;
+	tv->tv_sec = tm_to_time_t(&tm);
+	if (tv->tv_sec < 0)
+		return -1;
+	tv->tv_usec = st.wMilliseconds*1000;
+	return 0;
+}
+
+int pipe(int filedes[2])
+{
+	int fd;
+	HANDLE h[2], parent;
+
+	if (_pipe(filedes, 8192, 0) < 0)
+		return -1;
+
+	parent = GetCurrentProcess();
+
+	if (!DuplicateHandle (parent, (HANDLE)_get_osfhandle(filedes[0]),
+			parent, &h[0], 0, FALSE, DUPLICATE_SAME_ACCESS)) {
+		close(filedes[0]);
+		close(filedes[1]);
+		return -1;
+	}
+	if (!DuplicateHandle (parent, (HANDLE)_get_osfhandle(filedes[1]),
+			parent, &h[1], 0, FALSE, DUPLICATE_SAME_ACCESS)) {
+		close(filedes[0]);
+		close(filedes[1]);
+		CloseHandle(h[0]);
+		return -1;
+	}
+	fd = _open_osfhandle((int)h[0], O_NOINHERIT);
+	if (fd < 0) {
+		close(filedes[0]);
+		close(filedes[1]);
+		CloseHandle(h[0]);
+		CloseHandle(h[1]);
+		return -1;
+	}
+	close(filedes[0]);
+	filedes[0] = fd;
+	fd = _open_osfhandle((int)h[1], O_NOINHERIT);
+	if (fd < 0) {
+		close(filedes[0]);
+		close(filedes[1]);
+		CloseHandle(h[1]);
+		return -1;
+	}
+	close(filedes[1]);
+	filedes[1] = fd;
+	return 0;
+}
+
+int poll(struct pollfd *ufds, unsigned int nfds, int timeout)
+{
+	int i, pending;
+
+	if (timeout != -1)
+		return errno = EINVAL, error("poll timeout not supported");
+
+	/* When there is only one fd to wait for, then we pretend that
+	 * input is available and let the actual wait happen when the
+	 * caller invokes read().
+	 */
+	if (nfds == 1) {
+		if (!(ufds[0].events & POLLIN))
+			return errno = EINVAL, error("POLLIN not set");
+		ufds[0].revents = POLLIN;
+		return 0;
+	}
+
+repeat:
+	pending = 0;
+	for (i = 0; i < nfds; i++) {
+		DWORD avail = 0;
+		HANDLE h = (HANDLE) _get_osfhandle(ufds[i].fd);
+		if (h == INVALID_HANDLE_VALUE)
+			return -1;	/* errno was set */
+
+		if (!(ufds[i].events & POLLIN))
+			return errno = EINVAL, error("POLLIN not set");
+
+		/* this emulation works only for pipes */
+		if (!PeekNamedPipe(h, NULL, 0, NULL, &avail, NULL)) {
+			int err = GetLastError();
+			if (err == ERROR_BROKEN_PIPE) {
+				ufds[i].revents = POLLHUP;
+				pending++;
+			} else {
+				errno = EINVAL;
+				return error("PeekNamedPipe failed,"
+					" GetLastError: %u", err);
+			}
+		} else if (avail) {
+			ufds[i].revents = POLLIN;
+			pending++;
+		} else
+			ufds[i].revents = 0;
+	}
+	if (!pending) {
+		/* The only times that we spin here is when the process
+		 * that is connected through the pipes is waiting for
+		 * its own input data to become available. But since
+		 * the process (pack-objects) is itself CPU intensive,
+		 * it will happily pick up the time slice that we are
+		 * relinguishing here.
+		 */
+		Sleep(0);
+		goto repeat;
+	}
+	return 0;
+}
+
+struct tm *gmtime_r(const time_t *timep, struct tm *result)
+{
+	/* gmtime() in MSVCRT.DLL is thread-safe, but not reentrant */
+	memcpy(result, gmtime(timep), sizeof(struct tm));
+	return result;
+}
+
+struct tm *localtime_r(const time_t *timep, struct tm *result)
+{
+	/* localtime() in MSVCRT.DLL is thread-safe, but not reentrant */
+	memcpy(result, localtime(timep), sizeof(struct tm));
+	return result;
+}
+
+#undef getcwd
+char *mingw_getcwd(char *pointer, int len)
+{
+	int i;
+	char *ret = getcwd(pointer, len);
+	if (!ret)
+		return ret;
+	for (i = 0; pointer[i]; i++)
+		if (pointer[i] == '\\')
+			pointer[i] = '/';
+	return ret;
+}
+
+#undef getenv
+char *mingw_getenv(const char *name)
+{
+	char *result = getenv(name);
+	if (!result && !strcmp(name, "TMPDIR")) {
+		/* on Windows it is TMP and TEMP */
+		result = getenv("TMP");
+		if (!result)
+			result = getenv("TEMP");
+	}
+	return result;
+}
+
+/*
+ * See http://msdn2.microsoft.com/en-us/library/17w5ykft(vs.71).aspx
+ * (Parsing C++ Command-Line Arguments)
+ */
+static const char *quote_arg(const char *arg)
+{
+	/* count chars to quote */
+	int len = 0, n = 0;
+	int force_quotes = 0;
+	char *q, *d;
+	const char *p = arg;
+	if (!*p) force_quotes = 1;
+	while (*p) {
+		if (isspace(*p) || *p == '*' || *p == '?' || *p == '{')
+			force_quotes = 1;
+		else if (*p == '"')
+			n++;
+		else if (*p == '\\') {
+			int count = 0;
+			while (*p == '\\') {
+				count++;
+				p++;
+				len++;
+			}
+			if (*p == '"')
+				n += count*2 + 1;
+			continue;
+		}
+		len++;
+		p++;
+	}
+	if (!force_quotes && n == 0)
+		return arg;
+
+	/* insert \ where necessary */
+	d = q = xmalloc(len+n+3);
+	*d++ = '"';
+	while (*arg) {
+		if (*arg == '"')
+			*d++ = '\\';
+		else if (*arg == '\\') {
+			int count = 0;
+			while (*arg == '\\') {
+				count++;
+				*d++ = *arg++;
+			}
+			if (*arg == '"') {
+				while (count-- > 0)
+					*d++ = '\\';
+				*d++ = '\\';
+			}
+		}
+		*d++ = *arg++;
+	}
+	*d++ = '"';
+	*d++ = 0;
+	return q;
+}
+
+static const char *parse_interpreter(const char *cmd)
+{
+	static char buf[100];
+	char *p, *opt;
+	int n, fd;
+
+	/* don't even try a .exe */
+	n = strlen(cmd);
+	if (n >= 4 && !strcasecmp(cmd+n-4, ".exe"))
+		return NULL;
+
+	fd = open(cmd, O_RDONLY);
+	if (fd < 0)
+		return NULL;
+	n = read(fd, buf, sizeof(buf)-1);
+	close(fd);
+	if (n < 4)	/* at least '#!/x' and not error */
+		return NULL;
+
+	if (buf[0] != '#' || buf[1] != '!')
+		return NULL;
+	buf[n] = '\0';
+	p = strchr(buf, '\n');
+	if (!p)
+		return NULL;
+
+	*p = '\0';
+	if (!(p = strrchr(buf+2, '/')) && !(p = strrchr(buf+2, '\\')))
+		return NULL;
+	/* strip options */
+	if ((opt = strchr(p+1, ' ')))
+		*opt = '\0';
+	return p+1;
+}
+
+/*
+ * Splits the PATH into parts.
+ */
+static char **get_path_split(void)
+{
+	char *p, **path, *envpath = getenv("PATH");
+	int i, n = 0;
+
+	if (!envpath || !*envpath)
+		return NULL;
+
+	envpath = xstrdup(envpath);
+	p = envpath;
+	while (p) {
+		char *dir = p;
+		p = strchr(p, ';');
+		if (p) *p++ = '\0';
+		if (*dir) {	/* not earlier, catches series of ; */
+			++n;
+		}
+	}
+	if (!n)
+		return NULL;
+
+	path = xmalloc((n+1)*sizeof(char*));
+	p = envpath;
+	i = 0;
+	do {
+		if (*p)
+			path[i++] = xstrdup(p);
+		p = p+strlen(p)+1;
+	} while (i < n);
+	path[i] = NULL;
+
+	free(envpath);
+
+	return path;
+}
+
+static void free_path_split(char **path)
+{
+	if (!path)
+		return;
+
+	char **p = path;
+	while (*p)
+		free(*p++);
+	free(path);
+}
+
+/*
+ * exe_only means that we only want to detect .exe files, but not scripts
+ * (which do not have an extension)
+ */
+static char *lookup_prog(const char *dir, const char *cmd, int isexe, int exe_only)
+{
+	char path[MAX_PATH];
+	snprintf(path, sizeof(path), "%s/%s.exe", dir, cmd);
+
+	if (!isexe && access(path, F_OK) == 0)
+		return xstrdup(path);
+	path[strlen(path)-4] = '\0';
+	if ((!exe_only || isexe) && access(path, F_OK) == 0)
+		return xstrdup(path);
+	return NULL;
+}
+
+/*
+ * Determines the absolute path of cmd using the the split path in path.
+ * If cmd contains a slash or backslash, no lookup is performed.
+ */
+static char *path_lookup(const char *cmd, char **path, int exe_only)
+{
+	char *prog = NULL;
+	int len = strlen(cmd);
+	int isexe = len >= 4 && !strcasecmp(cmd+len-4, ".exe");
+
+	if (strchr(cmd, '/') || strchr(cmd, '\\'))
+		prog = xstrdup(cmd);
+
+	while (!prog && *path)
+		prog = lookup_prog(*path++, cmd, isexe, exe_only);
+
+	return prog;
+}
+
+static int env_compare(const void *a, const void *b)
+{
+	char *const *ea = a;
+	char *const *eb = b;
+	return strcasecmp(*ea, *eb);
+}
+
+static pid_t mingw_spawnve(const char *cmd, const char **argv, char **env,
+			   int prepend_cmd)
+{
+	STARTUPINFO si;
+	PROCESS_INFORMATION pi;
+	struct strbuf envblk, args;
+	unsigned flags;
+	BOOL ret;
+
+	/* Determine whether or not we are associated to a console */
+	HANDLE cons = CreateFile("CONOUT$", GENERIC_WRITE,
+			FILE_SHARE_WRITE, NULL, OPEN_EXISTING,
+			FILE_ATTRIBUTE_NORMAL, NULL);
+	if (cons == INVALID_HANDLE_VALUE) {
+		/* There is no console associated with this process.
+		 * Since the child is a console process, Windows
+		 * would normally create a console window. But
+		 * since we'll be redirecting std streams, we do
+		 * not need the console.
+		 */
+		flags = CREATE_NO_WINDOW;
+	} else {
+		/* There is already a console. If we specified
+		 * CREATE_NO_WINDOW here, too, Windows would
+		 * disassociate the child from the console.
+		 * Go figure!
+		 */
+		flags = 0;
+		CloseHandle(cons);
+	}
+	memset(&si, 0, sizeof(si));
+	si.cb = sizeof(si);
+	si.dwFlags = STARTF_USESTDHANDLES;
+	si.hStdInput = (HANDLE) _get_osfhandle(0);
+	si.hStdOutput = (HANDLE) _get_osfhandle(1);
+	si.hStdError = (HANDLE) _get_osfhandle(2);
+
+	/* concatenate argv, quoting args as we go */
+	strbuf_init(&args, 0);
+	if (prepend_cmd) {
+		char *quoted = (char *)quote_arg(cmd);
+		strbuf_addstr(&args, quoted);
+		if (quoted != cmd)
+			free(quoted);
+	}
+	for (; *argv; argv++) {
+		char *quoted = (char *)quote_arg(*argv);
+		if (*args.buf)
+			strbuf_addch(&args, ' ');
+		strbuf_addstr(&args, quoted);
+		if (quoted != *argv)
+			free(quoted);
+	}
+
+	if (env) {
+		int count = 0;
+		char **e, **sorted_env;
+
+		for (e = env; *e; e++)
+			count++;
+
+		/* environment must be sorted */
+		sorted_env = xmalloc(sizeof(*sorted_env) * (count + 1));
+		memcpy(sorted_env, env, sizeof(*sorted_env) * (count + 1));
+		qsort(sorted_env, count, sizeof(*sorted_env), env_compare);
+
+		strbuf_init(&envblk, 0);
+		for (e = sorted_env; *e; e++) {
+			strbuf_addstr(&envblk, *e);
+			strbuf_addch(&envblk, '\0');
+		}
+		free(sorted_env);
+	}
+
+	memset(&pi, 0, sizeof(pi));
+	ret = CreateProcess(cmd, args.buf, NULL, NULL, TRUE, flags,
+		env ? envblk.buf : NULL, NULL, &si, &pi);
+
+	if (env)
+		strbuf_release(&envblk);
+	strbuf_release(&args);
+
+	if (!ret) {
+		errno = ENOENT;
+		return -1;
+	}
+	CloseHandle(pi.hThread);
+	return (pid_t)pi.hProcess;
+}
+
+pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **env)
+{
+	pid_t pid;
+	char **path = get_path_split();
+	char *prog = path_lookup(cmd, path, 0);
+
+	if (!prog) {
+		errno = ENOENT;
+		pid = -1;
+	}
+	else {
+		const char *interpr = parse_interpreter(prog);
+
+		if (interpr) {
+			const char *argv0 = argv[0];
+			char *iprog = path_lookup(interpr, path, 1);
+			argv[0] = prog;
+			if (!iprog) {
+				errno = ENOENT;
+				pid = -1;
+			}
+			else {
+				pid = mingw_spawnve(iprog, argv, env, 1);
+				free(iprog);
+			}
+			argv[0] = argv0;
+		}
+		else
+			pid = mingw_spawnve(prog, argv, env, 0);
+		free(prog);
+	}
+	free_path_split(path);
+	return pid;
+}
+
+static int try_shell_exec(const char *cmd, char *const *argv, char **env)
+{
+	const char *interpr = parse_interpreter(cmd);
+	char **path;
+	char *prog;
+	int pid = 0;
+
+	if (!interpr)
+		return 0;
+	path = get_path_split();
+	prog = path_lookup(interpr, path, 1);
+	if (prog) {
+		int argc = 0;
+		const char **argv2;
+		while (argv[argc]) argc++;
+		argv2 = xmalloc(sizeof(*argv) * (argc+1));
+		argv2[0] = (char *)cmd;	/* full path to the script file */
+		memcpy(&argv2[1], &argv[1], sizeof(*argv) * argc);
+		pid = mingw_spawnve(prog, argv2, env, 1);
+		if (pid >= 0) {
+			int status;
+			if (waitpid(pid, &status, 0) < 0)
+				status = 255;
+			exit(status);
+		}
+		pid = 1;	/* indicate that we tried but failed */
+		free(prog);
+		free(argv2);
+	}
+	free_path_split(path);
+	return pid;
+}
+
+static void mingw_execve(const char *cmd, char *const *argv, char *const *env)
+{
+	/* check if git_command is a shell script */
+	if (!try_shell_exec(cmd, argv, (char **)env)) {
+		int pid, status;
+
+		pid = mingw_spawnve(cmd, (const char **)argv, (char **)env, 0);
+		if (pid < 0)
+			return;
+		if (waitpid(pid, &status, 0) < 0)
+			status = 255;
+		exit(status);
+	}
+}
+
+void mingw_execvp(const char *cmd, char *const *argv)
+{
+	char **path = get_path_split();
+	char *prog = path_lookup(cmd, path, 0);
+
+	if (prog) {
+		mingw_execve(prog, argv, environ);
+		free(prog);
+	} else
+		errno = ENOENT;
+
+	free_path_split(path);
+}
+
+char **copy_environ()
+{
+	char **env;
+	int i = 0;
+	while (environ[i])
+		i++;
+	env = xmalloc((i+1)*sizeof(*env));
+	for (i = 0; environ[i]; i++)
+		env[i] = xstrdup(environ[i]);
+	env[i] = NULL;
+	return env;
+}
+
+void free_environ(char **env)
+{
+	int i;
+	for (i = 0; env[i]; i++)
+		free(env[i]);
+	free(env);
+}
+
+static int lookup_env(char **env, const char *name, size_t nmln)
+{
+	int i;
+
+	for (i = 0; env[i]; i++) {
+		if (0 == strncmp(env[i], name, nmln)
+		    && '=' == env[i][nmln])
+			/* matches */
+			return i;
+	}
+	return -1;
+}
+
+/*
+ * If name contains '=', then sets the variable, otherwise it unsets it
+ */
+char **env_setenv(char **env, const char *name)
+{
+	char *eq = strchrnul(name, '=');
+	int i = lookup_env(env, name, eq-name);
+
+	if (i < 0) {
+		if (*eq) {
+			for (i = 0; env[i]; i++)
+				;
+			env = xrealloc(env, (i+2)*sizeof(*env));
+			env[i] = xstrdup(name);
+			env[i+1] = NULL;
+		}
+	}
+	else {
+		free(env[i]);
+		if (*eq)
+			env[i] = xstrdup(name);
+		else
+			for (; env[i]; i++)
+				env[i] = env[i+1];
+	}
+	return env;
+}
+
+/* this is the first function to call into WS_32; initialize it */
+#undef gethostbyname
+struct hostent *mingw_gethostbyname(const char *host)
+{
+	WSADATA wsa;
+
+	if (WSAStartup(MAKEWORD(2,2), &wsa))
+		die("unable to initialize winsock subsystem, error %d",
+			WSAGetLastError());
+	atexit((void(*)(void)) WSACleanup);
+	return gethostbyname(host);
+}
+
+int mingw_socket(int domain, int type, int protocol)
+{
+	int sockfd;
+	SOCKET s = WSASocket(domain, type, protocol, NULL, 0, 0);
+	if (s == INVALID_SOCKET) {
+		/*
+		 * WSAGetLastError() values are regular BSD error codes
+		 * biased by WSABASEERR.
+		 * However, strerror() does not know about networking
+		 * specific errors, which are values beginning at 38 or so.
+		 * Therefore, we choose to leave the biased error code
+		 * in errno so that _if_ someone looks up the code somewhere,
+		 * then it is at least the number that are usually listed.
+		 */
+		errno = WSAGetLastError();
+		return -1;
+	}
+	/* convert into a file descriptor */
+	if ((sockfd = _open_osfhandle(s, O_RDWR|O_BINARY)) < 0) {
+		closesocket(s);
+		return error("unable to make a socket file descriptor: %s",
+			strerror(errno));
+	}
+	return sockfd;
+}
+
+#undef connect
+int mingw_connect(int sockfd, struct sockaddr *sa, size_t sz)
+{
+	SOCKET s = (SOCKET)_get_osfhandle(sockfd);
+	return connect(s, sa, sz);
+}
+
+#undef rename
+int mingw_rename(const char *pold, const char *pnew)
+{
+	/*
+	 * Try native rename() first to get errno right.
+	 * It is based on MoveFile(), which cannot overwrite existing files.
+	 */
+	if (!rename(pold, pnew))
+		return 0;
+	if (errno != EEXIST)
+		return -1;
+	if (MoveFileEx(pold, pnew, MOVEFILE_REPLACE_EXISTING))
+		return 0;
+	/* TODO: translate more errors */
+	if (GetLastError() == ERROR_ACCESS_DENIED) {
+		DWORD attrs = GetFileAttributes(pnew);
+		if (attrs != INVALID_FILE_ATTRIBUTES && (attrs & FILE_ATTRIBUTE_DIRECTORY)) {
+			errno = EISDIR;
+			return -1;
+		}
+	}
+	errno = EACCES;
+	return -1;
+}
+
+struct passwd *getpwuid(int uid)
+{
+	static char user_name[100];
+	static struct passwd p;
+
+	DWORD len = sizeof(user_name);
+	if (!GetUserName(user_name, &len))
+		return NULL;
+	p.pw_name = user_name;
+	p.pw_gecos = "unknown";
+	p.pw_dir = NULL;
+	return &p;
+}
+
+static HANDLE timer_event;
+static HANDLE timer_thread;
+static int timer_interval;
+static int one_shot;
+static sig_handler_t timer_fn = SIG_DFL;
+
+/* The timer works like this:
+ * The thread, ticktack(), is a trivial routine that most of the time
+ * only waits to receive the signal to terminate. The main thread tells
+ * the thread to terminate by setting the timer_event to the signalled
+ * state.
+ * But ticktack() interrupts the wait state after the timer's interval
+ * length to call the signal handler.
+ */
+
+static __stdcall unsigned ticktack(void *dummy)
+{
+	while (WaitForSingleObject(timer_event, timer_interval) == WAIT_TIMEOUT) {
+		if (timer_fn == SIG_DFL)
+			die("Alarm");
+		if (timer_fn != SIG_IGN)
+			timer_fn(SIGALRM);
+		if (one_shot)
+			break;
+	}
+	return 0;
+}
+
+static int start_timer_thread(void)
+{
+	timer_event = CreateEvent(NULL, FALSE, FALSE, NULL);
+	if (timer_event) {
+		timer_thread = (HANDLE) _beginthreadex(NULL, 0, ticktack, NULL, 0, NULL);
+		if (!timer_thread )
+			return errno = ENOMEM,
+				error("cannot start timer thread");
+	} else
+		return errno = ENOMEM,
+			error("cannot allocate resources for timer");
+	return 0;
+}
+
+static void stop_timer_thread(void)
+{
+	if (timer_event)
+		SetEvent(timer_event);	/* tell thread to terminate */
+	if (timer_thread) {
+		int rc = WaitForSingleObject(timer_thread, 1000);
+		if (rc == WAIT_TIMEOUT)
+			error("timer thread did not terminate timely");
+		else if (rc != WAIT_OBJECT_0)
+			error("waiting for timer thread failed: %lu",
+			      GetLastError());
+		CloseHandle(timer_thread);
+	}
+	if (timer_event)
+		CloseHandle(timer_event);
+	timer_event = NULL;
+	timer_thread = NULL;
+}
+
+static inline int is_timeval_eq(const struct timeval *i1, const struct timeval *i2)
+{
+	return i1->tv_sec == i2->tv_sec && i1->tv_usec == i2->tv_usec;
+}
+
+int setitimer(int type, struct itimerval *in, struct itimerval *out)
+{
+	static const struct timeval zero;
+	static int atexit_done;
+
+	if (out != NULL)
+		return errno = EINVAL,
+			error("setitimer param 3 != NULL not implemented");
+	if (!is_timeval_eq(&in->it_interval, &zero) &&
+	    !is_timeval_eq(&in->it_interval, &in->it_value))
+		return errno = EINVAL,
+			error("setitimer: it_interval must be zero or eq it_value");
+
+	if (timer_thread)
+		stop_timer_thread();
+
+	if (is_timeval_eq(&in->it_value, &zero) &&
+	    is_timeval_eq(&in->it_interval, &zero))
+		return 0;
+
+	timer_interval = in->it_value.tv_sec * 1000 + in->it_value.tv_usec / 1000;
+	one_shot = is_timeval_eq(&in->it_interval, &zero);
+	if (!atexit_done) {
+		atexit(stop_timer_thread);
+		atexit_done = 1;
+	}
+	return start_timer_thread();
+}
+
+int sigaction(int sig, struct sigaction *in, struct sigaction *out)
+{
+	if (sig != SIGALRM)
+		return errno = EINVAL,
+			error("sigaction only implemented for SIGALRM");
+	if (out != NULL)
+		return errno = EINVAL,
+			error("sigaction: param 3 != NULL not implemented");
+
+	timer_fn = in->sa_handler;
+	return 0;
+}
+
+#undef signal
+sig_handler_t mingw_signal(int sig, sig_handler_t handler)
+{
+	if (sig != SIGALRM)
+		return signal(sig, handler);
+	sig_handler_t old = timer_fn;
+	timer_fn = handler;
+	return old;
+}
diff --git a/compat/mingw.h b/compat/mingw.h
new file mode 100644
index 000000000..6bc049ad9
--- /dev/null
+++ b/compat/mingw.h
@@ -0,0 +1,211 @@
+#include <winsock2.h>
+
+/*
+ * things that are not available in header files
+ */
+
+typedef int pid_t;
+#define hstrerror strerror
+
+#define S_IFLNK    0120000 /* Symbolic link */
+#define S_ISLNK(x) (((x) & S_IFMT) == S_IFLNK)
+#define S_ISSOCK(x) 0
+#define S_IRGRP 0
+#define S_IWGRP 0
+#define S_IXGRP 0
+#define S_ISGID 0
+#define S_IROTH 0
+#define S_IXOTH 0
+
+#define WIFEXITED(x) ((unsigned)(x) < 259)	/* STILL_ACTIVE */
+#define WEXITSTATUS(x) ((x) & 0xff)
+#define WIFSIGNALED(x) ((unsigned)(x) > 259)
+
+#define SIGKILL 0
+#define SIGCHLD 0
+#define SIGPIPE 0
+#define SIGHUP 0
+#define SIGQUIT 0
+#define SIGALRM 100
+
+#define F_GETFD 1
+#define F_SETFD 2
+#define FD_CLOEXEC 0x1
+
+struct passwd {
+	char *pw_name;
+	char *pw_gecos;
+	char *pw_dir;
+};
+
+struct pollfd {
+	int fd;           /* file descriptor */
+	short events;     /* requested events */
+	short revents;    /* returned events */
+};
+#define POLLIN 1
+#define POLLHUP 2
+
+typedef void (__cdecl *sig_handler_t)(int);
+struct sigaction {
+	sig_handler_t sa_handler;
+	unsigned sa_flags;
+};
+#define sigemptyset(x) (void)0
+#define SA_RESTART 0
+
+struct itimerval {
+	struct timeval it_value, it_interval;
+};
+#define ITIMER_REAL 0
+
+/*
+ * trivial stubs
+ */
+
+static inline int readlink(const char *path, char *buf, size_t bufsiz)
+{ errno = ENOSYS; return -1; }
+static inline int symlink(const char *oldpath, const char *newpath)
+{ errno = ENOSYS; return -1; }
+static inline int link(const char *oldpath, const char *newpath)
+{ errno = ENOSYS; return -1; }
+static inline int fchmod(int fildes, mode_t mode)
+{ errno = ENOSYS; return -1; }
+static inline int fork(void)
+{ errno = ENOSYS; return -1; }
+static inline unsigned int alarm(unsigned int seconds)
+{ return 0; }
+static inline int fsync(int fd)
+{ return 0; }
+static inline int getppid(void)
+{ return 1; }
+static inline void sync(void)
+{}
+static inline int getuid()
+{ return 1; }
+static inline struct passwd *getpwnam(const char *name)
+{ return NULL; }
+static inline int fcntl(int fd, int cmd, long arg)
+{
+	if (cmd == F_GETFD || cmd == F_SETFD)
+		return 0;
+	errno = EINVAL;
+	return -1;
+}
+
+/*
+ * simple adaptors
+ */
+
+static inline int mingw_mkdir(const char *path, int mode)
+{
+	return mkdir(path);
+}
+#define mkdir mingw_mkdir
+
+static inline int mingw_unlink(const char *pathname)
+{
+	/* read-only files cannot be removed */
+	chmod(pathname, 0666);
+	return unlink(pathname);
+}
+#define unlink mingw_unlink
+
+static inline int waitpid(pid_t pid, unsigned *status, unsigned options)
+{
+	if (options == 0)
+		return _cwait(status, pid, 0);
+	errno = EINVAL;
+	return -1;
+}
+
+/*
+ * implementations of missing functions
+ */
+
+int pipe(int filedes[2]);
+unsigned int sleep (unsigned int seconds);
+int mkstemp(char *template);
+int gettimeofday(struct timeval *tv, void *tz);
+int poll(struct pollfd *ufds, unsigned int nfds, int timeout);
+struct tm *gmtime_r(const time_t *timep, struct tm *result);
+struct tm *localtime_r(const time_t *timep, struct tm *result);
+int getpagesize(void);	/* defined in MinGW's libgcc.a */
+struct passwd *getpwuid(int uid);
+int setitimer(int type, struct itimerval *in, struct itimerval *out);
+int sigaction(int sig, struct sigaction *in, struct sigaction *out);
+
+/*
+ * replacements of existing functions
+ */
+
+int mingw_open (const char *filename, int oflags, ...);
+#define open mingw_open
+
+char *mingw_getcwd(char *pointer, int len);
+#define getcwd mingw_getcwd
+
+char *mingw_getenv(const char *name);
+#define getenv mingw_getenv
+
+struct hostent *mingw_gethostbyname(const char *host);
+#define gethostbyname mingw_gethostbyname
+
+int mingw_socket(int domain, int type, int protocol);
+#define socket mingw_socket
+
+int mingw_connect(int sockfd, struct sockaddr *sa, size_t sz);
+#define connect mingw_connect
+
+int mingw_rename(const char*, const char*);
+#define rename mingw_rename
+
+/* Use mingw_lstat() instead of lstat()/stat() and
+ * mingw_fstat() instead of fstat() on Windows.
+ * struct stat is redefined because it lacks the st_blocks member.
+ */
+struct mingw_stat {
+	unsigned st_mode;
+	time_t st_mtime, st_atime, st_ctime;
+	unsigned st_dev, st_ino, st_uid, st_gid;
+	size_t st_size;
+	size_t st_blocks;
+};
+int mingw_lstat(const char *file_name, struct mingw_stat *buf);
+int mingw_fstat(int fd, struct mingw_stat *buf);
+#define fstat mingw_fstat
+#define lstat mingw_lstat
+#define stat mingw_stat
+static inline int mingw_stat(const char *file_name, struct mingw_stat *buf)
+{ return mingw_lstat(file_name, buf); }
+
+int mingw_utime(const char *file_name, const struct utimbuf *times);
+#define utime mingw_utime
+
+pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **env);
+void mingw_execvp(const char *cmd, char *const *argv);
+#define execvp mingw_execvp
+
+static inline unsigned int git_ntohl(unsigned int x)
+{ return (unsigned int)ntohl(x); }
+#define ntohl git_ntohl
+
+sig_handler_t mingw_signal(int sig, sig_handler_t handler);
+#define signal mingw_signal
+
+/*
+ * git specific compatibility
+ */
+
+#define has_dos_drive_prefix(path) (isalpha(*(path)) && (path)[1] == ':')
+#define is_dir_sep(c) ((c) == '/' || (c) == '\\')
+#define PATH_SEP ';'
+#define PRIuMAX "I64u"
+
+/*
+ * helpers
+ */
+
+char **copy_environ(void);
+void free_environ(char **env);
+char **env_setenv(char **env, const char *name);
diff --git a/compat/regex.c b/compat/regex.c
new file mode 100644
index 000000000..87b33e466
--- /dev/null
+++ b/compat/regex.c
@@ -0,0 +1,4927 @@
+/* Extended regular expression matching and search library,
+   version 0.12.
+   (Implements POSIX draft P10003.2/D11.2, except for
+   internationalization features.)
+
+   Copyright (C) 1993 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* AIX requires this to be the first thing in the file. */
+#if defined (_AIX) && !defined (REGEX_MALLOC)
+  #pragma alloca
+#endif
+
+#define _GNU_SOURCE
+
+/* We need this for `regex.h', and perhaps for the Emacs include files.  */
+#include <sys/types.h>
+
+/* We used to test for `BSTRING' here, but only GCC and Emacs define
+   `BSTRING', as far as I know, and neither of them use this code.  */
+#include <string.h>
+#ifndef bcmp
+#define bcmp(s1, s2, n)	memcmp ((s1), (s2), (n))
+#endif
+#ifndef bcopy
+#define bcopy(s, d, n)	memcpy ((d), (s), (n))
+#endif
+#ifndef bzero
+#define bzero(s, n)	memset ((s), 0, (n))
+#endif
+
+#include <stdlib.h>
+
+
+/* Define the syntax stuff for \<, \>, etc.  */
+
+/* This must be nonzero for the wordchar and notwordchar pattern
+   commands in re_match_2.  */
+#ifndef Sword
+#define Sword 1
+#endif
+
+#ifdef SYNTAX_TABLE
+
+extern char *re_syntax_table;
+
+#else /* not SYNTAX_TABLE */
+
+/* How many characters in the character set.  */
+#define CHAR_SET_SIZE 256
+
+static char re_syntax_table[CHAR_SET_SIZE];
+
+static void
+init_syntax_once ()
+{
+   register int c;
+   static int done = 0;
+
+   if (done)
+     return;
+
+   bzero (re_syntax_table, sizeof re_syntax_table);
+
+   for (c = 'a'; c <= 'z'; c++)
+     re_syntax_table[c] = Sword;
+
+   for (c = 'A'; c <= 'Z'; c++)
+     re_syntax_table[c] = Sword;
+
+   for (c = '0'; c <= '9'; c++)
+     re_syntax_table[c] = Sword;
+
+   re_syntax_table['_'] = Sword;
+
+   done = 1;
+}
+
+#endif /* not SYNTAX_TABLE */
+
+#define SYNTAX(c) re_syntax_table[c]
+
+
+/* Get the interface, including the syntax bits.  */
+#include "regex.h"
+
+/* isalpha etc. are used for the character classes.  */
+#include <ctype.h>
+
+#ifndef isascii
+#define isascii(c) 1
+#endif
+
+#ifdef isblank
+#define ISBLANK(c) (isascii (c) && isblank (c))
+#else
+#define ISBLANK(c) ((c) == ' ' || (c) == '\t')
+#endif
+#ifdef isgraph
+#define ISGRAPH(c) (isascii (c) && isgraph (c))
+#else
+#define ISGRAPH(c) (isascii (c) && isprint (c) && !isspace (c))
+#endif
+
+#define ISPRINT(c) (isascii (c) && isprint (c))
+#define ISDIGIT(c) (isascii (c) && isdigit (c))
+#define ISALNUM(c) (isascii (c) && isalnum (c))
+#define ISALPHA(c) (isascii (c) && isalpha (c))
+#define ISCNTRL(c) (isascii (c) && iscntrl (c))
+#define ISLOWER(c) (isascii (c) && islower (c))
+#define ISPUNCT(c) (isascii (c) && ispunct (c))
+#define ISSPACE(c) (isascii (c) && isspace (c))
+#define ISUPPER(c) (isascii (c) && isupper (c))
+#define ISXDIGIT(c) (isascii (c) && isxdigit (c))
+
+#ifndef NULL
+#define NULL 0
+#endif
+
+/* We remove any previous definition of `SIGN_EXTEND_CHAR',
+   since ours (we hope) works properly with all combinations of
+   machines, compilers, `char' and `unsigned char' argument types.
+   (Per Bothner suggested the basic approach.)  */
+#undef SIGN_EXTEND_CHAR
+#if __STDC__
+#define SIGN_EXTEND_CHAR(c) ((signed char) (c))
+#else  /* not __STDC__ */
+/* As in Harbison and Steele.  */
+#define SIGN_EXTEND_CHAR(c) ((((unsigned char) (c)) ^ 128) - 128)
+#endif
+
+/* Should we use malloc or alloca?  If REGEX_MALLOC is not defined, we
+   use `alloca' instead of `malloc'.  This is because using malloc in
+   re_search* or re_match* could cause memory leaks when C-g is used in
+   Emacs; also, malloc is slower and causes storage fragmentation.  On
+   the other hand, malloc is more portable, and easier to debug.
+
+   Because we sometimes use alloca, some routines have to be macros,
+   not functions -- `alloca'-allocated space disappears at the end of the
+   function it is called in.  */
+
+#ifdef REGEX_MALLOC
+
+#define REGEX_ALLOCATE malloc
+#define REGEX_REALLOCATE(source, osize, nsize) realloc (source, nsize)
+
+#else /* not REGEX_MALLOC  */
+
+/* Emacs already defines alloca, sometimes.  */
+#ifndef alloca
+
+/* Make alloca work the best possible way.  */
+#ifdef __GNUC__
+#define alloca __builtin_alloca
+#else /* not __GNUC__ */
+#if HAVE_ALLOCA_H
+#include <alloca.h>
+#else /* not __GNUC__ or HAVE_ALLOCA_H */
+#ifndef _AIX /* Already did AIX, up at the top.  */
+char *alloca ();
+#endif /* not _AIX */
+#endif /* not HAVE_ALLOCA_H */
+#endif /* not __GNUC__ */
+
+#endif /* not alloca */
+
+#define REGEX_ALLOCATE alloca
+
+/* Assumes a `char *destination' variable.  */
+#define REGEX_REALLOCATE(source, osize, nsize)				\
+  (destination = (char *) alloca (nsize),				\
+   bcopy (source, destination, osize),					\
+   destination)
+
+#endif /* not REGEX_MALLOC */
+
+
+/* True if `size1' is non-NULL and PTR is pointing anywhere inside
+   `string1' or just past its end.  This works if PTR is NULL, which is
+   a good thing.  */
+#define FIRST_STRING_P(ptr) 					\
+  (size1 && string1 <= (ptr) && (ptr) <= string1 + size1)
+
+/* (Re)Allocate N items of type T using malloc, or fail.  */
+#define TALLOC(n, t) ((t *) malloc ((n) * sizeof (t)))
+#define RETALLOC(addr, n, t) ((addr) = (t *) realloc (addr, (n) * sizeof (t)))
+#define REGEX_TALLOC(n, t) ((t *) REGEX_ALLOCATE ((n) * sizeof (t)))
+
+#define BYTEWIDTH 8 /* In bits.  */
+
+#define STREQ(s1, s2) ((strcmp (s1, s2) == 0))
+
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+typedef char boolean;
+#define false 0
+#define true 1
+
+/* These are the command codes that appear in compiled regular
+   expressions.  Some opcodes are followed by argument bytes.  A
+   command code can specify any interpretation whatsoever for its
+   arguments.  Zero bytes may appear in the compiled regular expression.
+
+   The value of `exactn' is needed in search.c (search_buffer) in Emacs.
+   So regex.h defines a symbol `RE_EXACTN_VALUE' to be 1; the value of
+   `exactn' we use here must also be 1.  */
+
+typedef enum
+{
+  no_op = 0,
+
+	/* Followed by one byte giving n, then by n literal bytes.  */
+  exactn = 1,
+
+	/* Matches any (more or less) character.  */
+  anychar,
+
+	/* Matches any one char belonging to specified set.  First
+	   following byte is number of bitmap bytes.  Then come bytes
+	   for a bitmap saying which chars are in.  Bits in each byte
+	   are ordered low-bit-first.  A character is in the set if its
+	   bit is 1.  A character too large to have a bit in the map is
+	   automatically not in the set.  */
+  charset,
+
+	/* Same parameters as charset, but match any character that is
+	   not one of those specified.  */
+  charset_not,
+
+	/* Start remembering the text that is matched, for storing in a
+	   register.  Followed by one byte with the register number, in
+	   the range 0 to one less than the pattern buffer's re_nsub
+	   field.  Then followed by one byte with the number of groups
+	   inner to this one.  (This last has to be part of the
+	   start_memory only because we need it in the on_failure_jump
+	   of re_match_2.)  */
+  start_memory,
+
+	/* Stop remembering the text that is matched and store it in a
+	   memory register.  Followed by one byte with the register
+	   number, in the range 0 to one less than `re_nsub' in the
+	   pattern buffer, and one byte with the number of inner groups,
+	   just like `start_memory'.  (We need the number of inner
+	   groups here because we don't have any easy way of finding the
+	   corresponding start_memory when we're at a stop_memory.)  */
+  stop_memory,
+
+	/* Match a duplicate of something remembered. Followed by one
+	   byte containing the register number.  */
+  duplicate,
+
+	/* Fail unless at beginning of line.  */
+  begline,
+
+	/* Fail unless at end of line.  */
+  endline,
+
+	/* Succeeds if at beginning of buffer (if emacs) or at beginning
+	   of string to be matched (if not).  */
+  begbuf,
+
+	/* Analogously, for end of buffer/string.  */
+  endbuf,
+
+	/* Followed by two byte relative address to which to jump.  */
+  jump,
+
+	/* Same as jump, but marks the end of an alternative.  */
+  jump_past_alt,
+
+	/* Followed by two-byte relative address of place to resume at
+	   in case of failure.  */
+  on_failure_jump,
+
+	/* Like on_failure_jump, but pushes a placeholder instead of the
+	   current string position when executed.  */
+  on_failure_keep_string_jump,
+
+	/* Throw away latest failure point and then jump to following
+	   two-byte relative address.  */
+  pop_failure_jump,
+
+	/* Change to pop_failure_jump if know won't have to backtrack to
+	   match; otherwise change to jump.  This is used to jump
+	   back to the beginning of a repeat.  If what follows this jump
+	   clearly won't match what the repeat does, such that we can be
+	   sure that there is no use backtracking out of repetitions
+	   already matched, then we change it to a pop_failure_jump.
+	   Followed by two-byte address.  */
+  maybe_pop_jump,
+
+	/* Jump to following two-byte address, and push a dummy failure
+	   point. This failure point will be thrown away if an attempt
+	   is made to use it for a failure.  A `+' construct makes this
+	   before the first repeat.  Also used as an intermediary kind
+	   of jump when compiling an alternative.  */
+  dummy_failure_jump,
+
+	/* Push a dummy failure point and continue.  Used at the end of
+	   alternatives.  */
+  push_dummy_failure,
+
+	/* Followed by two-byte relative address and two-byte number n.
+	   After matching N times, jump to the address upon failure.  */
+  succeed_n,
+
+	/* Followed by two-byte relative address, and two-byte number n.
+	   Jump to the address N times, then fail.  */
+  jump_n,
+
+	/* Set the following two-byte relative address to the
+	   subsequent two-byte number.  The address *includes* the two
+	   bytes of number.  */
+  set_number_at,
+
+  wordchar,	/* Matches any word-constituent character.  */
+  notwordchar,	/* Matches any char that is not a word-constituent.  */
+
+  wordbeg,	/* Succeeds if at word beginning.  */
+  wordend,	/* Succeeds if at word end.  */
+
+  wordbound,	/* Succeeds if at a word boundary.  */
+  notwordbound	/* Succeeds if not at a word boundary.  */
+
+#ifdef emacs
+  ,before_dot,	/* Succeeds if before point.  */
+  at_dot,	/* Succeeds if at point.  */
+  after_dot,	/* Succeeds if after point.  */
+
+	/* Matches any character whose syntax is specified.  Followed by
+	   a byte which contains a syntax code, e.g., Sword.  */
+  syntaxspec,
+
+	/* Matches any character whose syntax is not that specified.  */
+  notsyntaxspec
+#endif /* emacs */
+} re_opcode_t;
+
+/* Common operations on the compiled pattern.  */
+
+/* Store NUMBER in two contiguous bytes starting at DESTINATION.  */
+
+#define STORE_NUMBER(destination, number)				\
+  do {									\
+    (destination)[0] = (number) & 0377;					\
+    (destination)[1] = (number) >> 8;					\
+  } while (0)
+
+/* Same as STORE_NUMBER, except increment DESTINATION to
+   the byte after where the number is stored.  Therefore, DESTINATION
+   must be an lvalue.  */
+
+#define STORE_NUMBER_AND_INCR(destination, number)			\
+  do {									\
+    STORE_NUMBER (destination, number);					\
+    (destination) += 2;							\
+  } while (0)
+
+/* Put into DESTINATION a number stored in two contiguous bytes starting
+   at SOURCE.  */
+
+#define EXTRACT_NUMBER(destination, source)				\
+  do {									\
+    (destination) = *(source) & 0377;					\
+    (destination) += SIGN_EXTEND_CHAR (*((source) + 1)) << 8;		\
+  } while (0)
+
+#ifdef DEBUG
+static void
+extract_number (dest, source)
+    int *dest;
+    unsigned char *source;
+{
+  int temp = SIGN_EXTEND_CHAR (*(source + 1));
+  *dest = *source & 0377;
+  *dest += temp << 8;
+}
+
+#ifndef EXTRACT_MACROS /* To debug the macros.  */
+#undef EXTRACT_NUMBER
+#define EXTRACT_NUMBER(dest, src) extract_number (&dest, src)
+#endif /* not EXTRACT_MACROS */
+
+#endif /* DEBUG */
+
+/* Same as EXTRACT_NUMBER, except increment SOURCE to after the number.
+   SOURCE must be an lvalue.  */
+
+#define EXTRACT_NUMBER_AND_INCR(destination, source)			\
+  do {									\
+    EXTRACT_NUMBER (destination, source);				\
+    (source) += 2; 							\
+  } while (0)
+
+#ifdef DEBUG
+static void
+extract_number_and_incr (destination, source)
+    int *destination;
+    unsigned char **source;
+{
+  extract_number (destination, *source);
+  *source += 2;
+}
+
+#ifndef EXTRACT_MACROS
+#undef EXTRACT_NUMBER_AND_INCR
+#define EXTRACT_NUMBER_AND_INCR(dest, src) \
+  extract_number_and_incr (&dest, &src)
+#endif /* not EXTRACT_MACROS */
+
+#endif /* DEBUG */
+
+/* If DEBUG is defined, Regex prints many voluminous messages about what
+   it is doing (if the variable `debug' is nonzero).  If linked with the
+   main program in `iregex.c', you can enter patterns and strings
+   interactively.  And if linked with the main program in `main.c' and
+   the other test files, you can run the already-written tests.  */
+
+#ifdef DEBUG
+
+/* We use standard I/O for debugging.  */
+#include <stdio.h>
+
+/* It is useful to test things that ``must'' be true when debugging.  */
+#include <assert.h>
+
+static int debug = 0;
+
+#define DEBUG_STATEMENT(e) e
+#define DEBUG_PRINT1(x) if (debug) printf (x)
+#define DEBUG_PRINT2(x1, x2) if (debug) printf (x1, x2)
+#define DEBUG_PRINT3(x1, x2, x3) if (debug) printf (x1, x2, x3)
+#define DEBUG_PRINT4(x1, x2, x3, x4) if (debug) printf (x1, x2, x3, x4)
+#define DEBUG_PRINT_COMPILED_PATTERN(p, s, e) 				\
+  if (debug) print_partial_compiled_pattern (s, e)
+#define DEBUG_PRINT_DOUBLE_STRING(w, s1, sz1, s2, sz2)			\
+  if (debug) print_double_string (w, s1, sz1, s2, sz2)
+
+
+extern void printchar ();
+
+/* Print the fastmap in human-readable form.  */
+
+void
+print_fastmap (fastmap)
+    char *fastmap;
+{
+  unsigned was_a_range = 0;
+  unsigned i = 0;
+
+  while (i < (1 << BYTEWIDTH))
+    {
+      if (fastmap[i++])
+	{
+	  was_a_range = 0;
+	  printchar (i - 1);
+	  while (i < (1 << BYTEWIDTH)  &&  fastmap[i])
+	    {
+	      was_a_range = 1;
+	      i++;
+	    }
+	  if (was_a_range)
+	    {
+	      printf ("-");
+	      printchar (i - 1);
+	    }
+	}
+    }
+  putchar ('\n');
+}
+
+
+/* Print a compiled pattern string in human-readable form, starting at
+   the START pointer into it and ending just before the pointer END.  */
+
+void
+print_partial_compiled_pattern (start, end)
+    unsigned char *start;
+    unsigned char *end;
+{
+  int mcnt, mcnt2;
+  unsigned char *p = start;
+  unsigned char *pend = end;
+
+  if (start == NULL)
+    {
+      printf ("(null)\n");
+      return;
+    }
+
+  /* Loop over pattern commands.  */
+  while (p < pend)
+    {
+      switch ((re_opcode_t) *p++)
+	{
+	case no_op:
+	  printf ("/no_op");
+	  break;
+
+	case exactn:
+	  mcnt = *p++;
+	  printf ("/exactn/%d", mcnt);
+	  do
+	    {
+	      putchar ('/');
+	      printchar (*p++);
+	    }
+	  while (--mcnt);
+	  break;
+
+	case start_memory:
+	  mcnt = *p++;
+	  printf ("/start_memory/%d/%d", mcnt, *p++);
+	  break;
+
+	case stop_memory:
+	  mcnt = *p++;
+	  printf ("/stop_memory/%d/%d", mcnt, *p++);
+	  break;
+
+	case duplicate:
+	  printf ("/duplicate/%d", *p++);
+	  break;
+
+	case anychar:
+	  printf ("/anychar");
+	  break;
+
+	case charset:
+	case charset_not:
+	  {
+	    register int c;
+
+	    printf ("/charset%s",
+		    (re_opcode_t) *(p - 1) == charset_not ? "_not" : "");
+
+	    assert (p + *p < pend);
+
+	    for (c = 0; c < *p; c++)
+	      {
+		unsigned bit;
+		unsigned char map_byte = p[1 + c];
+
+		putchar ('/');
+
+		for (bit = 0; bit < BYTEWIDTH; bit++)
+		  if (map_byte & (1 << bit))
+		    printchar (c * BYTEWIDTH + bit);
+	      }
+	    p += 1 + *p;
+	    break;
+	  }
+
+	case begline:
+	  printf ("/begline");
+	  break;
+
+	case endline:
+	  printf ("/endline");
+	  break;
+
+	case on_failure_jump:
+	  extract_number_and_incr (&mcnt, &p);
+	  printf ("/on_failure_jump/0/%d", mcnt);
+	  break;
+
+	case on_failure_keep_string_jump:
+	  extract_number_and_incr (&mcnt, &p);
+	  printf ("/on_failure_keep_string_jump/0/%d", mcnt);
+	  break;
+
+	case dummy_failure_jump:
+	  extract_number_and_incr (&mcnt, &p);
+	  printf ("/dummy_failure_jump/0/%d", mcnt);
+	  break;
+
+	case push_dummy_failure:
+	  printf ("/push_dummy_failure");
+	  break;
+
+	case maybe_pop_jump:
+	  extract_number_and_incr (&mcnt, &p);
+	  printf ("/maybe_pop_jump/0/%d", mcnt);
+	  break;
+
+	case pop_failure_jump:
+	  extract_number_and_incr (&mcnt, &p);
+	  printf ("/pop_failure_jump/0/%d", mcnt);
+	  break;
+
+	case jump_past_alt:
+	  extract_number_and_incr (&mcnt, &p);
+	  printf ("/jump_past_alt/0/%d", mcnt);
+	  break;
+
+	case jump:
+	  extract_number_and_incr (&mcnt, &p);
+	  printf ("/jump/0/%d", mcnt);
+	  break;
+
+	case succeed_n:
+	  extract_number_and_incr (&mcnt, &p);
+	  extract_number_and_incr (&mcnt2, &p);
+	  printf ("/succeed_n/0/%d/0/%d", mcnt, mcnt2);
+	  break;
+
+	case jump_n:
+	  extract_number_and_incr (&mcnt, &p);
+	  extract_number_and_incr (&mcnt2, &p);
+	  printf ("/jump_n/0/%d/0/%d", mcnt, mcnt2);
+	  break;
+
+	case set_number_at:
+	  extract_number_and_incr (&mcnt, &p);
+	  extract_number_and_incr (&mcnt2, &p);
+	  printf ("/set_number_at/0/%d/0/%d", mcnt, mcnt2);
+	  break;
+
+	case wordbound:
+	  printf ("/wordbound");
+	  break;
+
+	case notwordbound:
+	  printf ("/notwordbound");
+	  break;
+
+	case wordbeg:
+	  printf ("/wordbeg");
+	  break;
+
+	case wordend:
+	  printf ("/wordend");
+
+#ifdef emacs
+	case before_dot:
+	  printf ("/before_dot");
+	  break;
+
+	case at_dot:
+	  printf ("/at_dot");
+	  break;
+
+	case after_dot:
+	  printf ("/after_dot");
+	  break;
+
+	case syntaxspec:
+	  printf ("/syntaxspec");
+	  mcnt = *p++;
+	  printf ("/%d", mcnt);
+	  break;
+
+	case notsyntaxspec:
+	  printf ("/notsyntaxspec");
+	  mcnt = *p++;
+	  printf ("/%d", mcnt);
+	  break;
+#endif /* emacs */
+
+	case wordchar:
+	  printf ("/wordchar");
+	  break;
+
+	case notwordchar:
+	  printf ("/notwordchar");
+	  break;
+
+	case begbuf:
+	  printf ("/begbuf");
+	  break;
+
+	case endbuf:
+	  printf ("/endbuf");
+	  break;
+
+	default:
+	  printf ("?%d", *(p-1));
+	}
+    }
+  printf ("/\n");
+}
+
+
+void
+print_compiled_pattern (bufp)
+    struct re_pattern_buffer *bufp;
+{
+  unsigned char *buffer = bufp->buffer;
+
+  print_partial_compiled_pattern (buffer, buffer + bufp->used);
+  printf ("%d bytes used/%d bytes allocated.\n", bufp->used, bufp->allocated);
+
+  if (bufp->fastmap_accurate && bufp->fastmap)
+    {
+      printf ("fastmap: ");
+      print_fastmap (bufp->fastmap);
+    }
+
+  printf ("re_nsub: %d\t", bufp->re_nsub);
+  printf ("regs_alloc: %d\t", bufp->regs_allocated);
+  printf ("can_be_null: %d\t", bufp->can_be_null);
+  printf ("newline_anchor: %d\n", bufp->newline_anchor);
+  printf ("no_sub: %d\t", bufp->no_sub);
+  printf ("not_bol: %d\t", bufp->not_bol);
+  printf ("not_eol: %d\t", bufp->not_eol);
+  printf ("syntax: %d\n", bufp->syntax);
+  /* Perhaps we should print the translate table?  */
+}
+
+
+void
+print_double_string (where, string1, size1, string2, size2)
+    const char *where;
+    const char *string1;
+    const char *string2;
+    int size1;
+    int size2;
+{
+  unsigned this_char;
+
+  if (where == NULL)
+    printf ("(null)");
+  else
+    {
+      if (FIRST_STRING_P (where))
+	{
+	  for (this_char = where - string1; this_char < size1; this_char++)
+	    printchar (string1[this_char]);
+
+	  where = string2;
+	}
+
+      for (this_char = where - string2; this_char < size2; this_char++)
+	printchar (string2[this_char]);
+    }
+}
+
+#else /* not DEBUG */
+
+#undef assert
+#define assert(e)
+
+#define DEBUG_STATEMENT(e)
+#define DEBUG_PRINT1(x)
+#define DEBUG_PRINT2(x1, x2)
+#define DEBUG_PRINT3(x1, x2, x3)
+#define DEBUG_PRINT4(x1, x2, x3, x4)
+#define DEBUG_PRINT_COMPILED_PATTERN(p, s, e)
+#define DEBUG_PRINT_DOUBLE_STRING(w, s1, sz1, s2, sz2)
+
+#endif /* not DEBUG */
+
+/* Set by `re_set_syntax' to the current regexp syntax to recognize.  Can
+   also be assigned to arbitrarily: each pattern buffer stores its own
+   syntax, so it can be changed between regex compilations.  */
+reg_syntax_t re_syntax_options = RE_SYNTAX_EMACS;
+
+
+/* Specify the precise syntax of regexps for compilation.  This provides
+   for compatibility for various utilities which historically have
+   different, incompatible syntaxes.
+
+   The argument SYNTAX is a bit mask comprised of the various bits
+   defined in regex.h.  We return the old syntax.  */
+
+reg_syntax_t
+re_set_syntax (syntax)
+    reg_syntax_t syntax;
+{
+  reg_syntax_t ret = re_syntax_options;
+
+  re_syntax_options = syntax;
+  return ret;
+}
+
+/* This table gives an error message for each of the error codes listed
+   in regex.h.  Obviously the order here has to be same as there.  */
+
+static const char *re_error_msg[] =
+  { NULL,					/* REG_NOERROR */
+    "No match",					/* REG_NOMATCH */
+    "Invalid regular expression",		/* REG_BADPAT */
+    "Invalid collation character",		/* REG_ECOLLATE */
+    "Invalid character class name",		/* REG_ECTYPE */
+    "Trailing backslash",			/* REG_EESCAPE */
+    "Invalid back reference",			/* REG_ESUBREG */
+    "Unmatched [ or [^",			/* REG_EBRACK */
+    "Unmatched ( or \\(",			/* REG_EPAREN */
+    "Unmatched \\{",				/* REG_EBRACE */
+    "Invalid content of \\{\\}",		/* REG_BADBR */
+    "Invalid range end",			/* REG_ERANGE */
+    "Memory exhausted",				/* REG_ESPACE */
+    "Invalid preceding regular expression",	/* REG_BADRPT */
+    "Premature end of regular expression",	/* REG_EEND */
+    "Regular expression too big",		/* REG_ESIZE */
+    "Unmatched ) or \\)",			/* REG_ERPAREN */
+  };
+
+/* Subroutine declarations and macros for regex_compile.  */
+
+static void store_op1 (), store_op2 ();
+static void insert_op1 (), insert_op2 ();
+static boolean at_begline_loc_p (), at_endline_loc_p ();
+static boolean group_in_compile_stack ();
+static reg_errcode_t compile_range ();
+
+/* Fetch the next character in the uncompiled pattern---translating it
+   if necessary.  Also cast from a signed character in the constant
+   string passed to us by the user to an unsigned char that we can use
+   as an array index (in, e.g., `translate').  */
+#define PATFETCH(c)							\
+  do {if (p == pend) return REG_EEND;					\
+    c = (unsigned char) *p++;						\
+    if (translate) c = translate[c]; 					\
+  } while (0)
+
+/* Fetch the next character in the uncompiled pattern, with no
+   translation.  */
+#define PATFETCH_RAW(c)							\
+  do {if (p == pend) return REG_EEND;					\
+    c = (unsigned char) *p++; 						\
+  } while (0)
+
+/* Go backwards one character in the pattern.  */
+#define PATUNFETCH p--
+
+
+/* If `translate' is non-null, return translate[D], else just D.  We
+   cast the subscript to translate because some data is declared as
+   `char *', to avoid warnings when a string constant is passed.  But
+   when we use a character as a subscript we must make it unsigned.  */
+#define TRANSLATE(d) (translate ? translate[(unsigned char) (d)] : (d))
+
+
+/* Macros for outputting the compiled pattern into `buffer'.  */
+
+/* If the buffer isn't allocated when it comes in, use this.  */
+#define INIT_BUF_SIZE  32
+
+/* Make sure we have at least N more bytes of space in buffer.  */
+#define GET_BUFFER_SPACE(n)						\
+    while (b - bufp->buffer + (n) > bufp->allocated)			\
+      EXTEND_BUFFER ()
+
+/* Make sure we have one more byte of buffer space and then add C to it.  */
+#define BUF_PUSH(c)							\
+  do {									\
+    GET_BUFFER_SPACE (1);						\
+    *b++ = (unsigned char) (c);						\
+  } while (0)
+
+
+/* Ensure we have two more bytes of buffer space and then append C1 and C2.  */
+#define BUF_PUSH_2(c1, c2)						\
+  do {									\
+    GET_BUFFER_SPACE (2);						\
+    *b++ = (unsigned char) (c1);					\
+    *b++ = (unsigned char) (c2);					\
+  } while (0)
+
+
+/* As with BUF_PUSH_2, except for three bytes.  */
+#define BUF_PUSH_3(c1, c2, c3)						\
+  do {									\
+    GET_BUFFER_SPACE (3);						\
+    *b++ = (unsigned char) (c1);					\
+    *b++ = (unsigned char) (c2);					\
+    *b++ = (unsigned char) (c3);					\
+  } while (0)
+
+
+/* Store a jump with opcode OP at LOC to location TO.  We store a
+   relative address offset by the three bytes the jump itself occupies.  */
+#define STORE_JUMP(op, loc, to) \
+  store_op1 (op, loc, (to) - (loc) - 3)
+
+/* Likewise, for a two-argument jump.  */
+#define STORE_JUMP2(op, loc, to, arg) \
+  store_op2 (op, loc, (to) - (loc) - 3, arg)
+
+/* Like `STORE_JUMP', but for inserting.  Assume `b' is the buffer end.  */
+#define INSERT_JUMP(op, loc, to) \
+  insert_op1 (op, loc, (to) - (loc) - 3, b)
+
+/* Like `STORE_JUMP2', but for inserting.  Assume `b' is the buffer end.  */
+#define INSERT_JUMP2(op, loc, to, arg) \
+  insert_op2 (op, loc, (to) - (loc) - 3, arg, b)
+
+
+/* This is not an arbitrary limit: the arguments which represent offsets
+   into the pattern are two bytes long.  So if 2^16 bytes turns out to
+   be too small, many things would have to change.  */
+#define MAX_BUF_SIZE (1L << 16)
+
+
+/* Extend the buffer by twice its current size via realloc and
+   reset the pointers that pointed into the old block to point to the
+   correct places in the new one.  If extending the buffer results in it
+   being larger than MAX_BUF_SIZE, then flag memory exhausted.  */
+#define EXTEND_BUFFER()							\
+  do { 									\
+    unsigned char *old_buffer = bufp->buffer;				\
+    if (bufp->allocated == MAX_BUF_SIZE) 				\
+      return REG_ESIZE;							\
+    bufp->allocated <<= 1;						\
+    if (bufp->allocated > MAX_BUF_SIZE)					\
+      bufp->allocated = MAX_BUF_SIZE; 					\
+    bufp->buffer = (unsigned char *) realloc (bufp->buffer, bufp->allocated);\
+    if (bufp->buffer == NULL)						\
+      return REG_ESPACE;						\
+    /* If the buffer moved, move all the pointers into it.  */		\
+    if (old_buffer != bufp->buffer)					\
+      {									\
+	b = (b - old_buffer) + bufp->buffer;				\
+	begalt = (begalt - old_buffer) + bufp->buffer;			\
+	if (fixup_alt_jump)						\
+	  fixup_alt_jump = (fixup_alt_jump - old_buffer) + bufp->buffer;\
+	if (laststart)							\
+	  laststart = (laststart - old_buffer) + bufp->buffer;		\
+	if (pending_exact)						\
+	  pending_exact = (pending_exact - old_buffer) + bufp->buffer;	\
+      }									\
+  } while (0)
+
+
+/* Since we have one byte reserved for the register number argument to
+   {start,stop}_memory, the maximum number of groups we can report
+   things about is what fits in that byte.  */
+#define MAX_REGNUM 255
+
+/* But patterns can have more than `MAX_REGNUM' registers.  We just
+   ignore the excess.  */
+typedef unsigned regnum_t;
+
+
+/* Macros for the compile stack.  */
+
+/* Since offsets can go either forwards or backwards, this type needs to
+   be able to hold values from -(MAX_BUF_SIZE - 1) to MAX_BUF_SIZE - 1.  */
+typedef int pattern_offset_t;
+
+typedef struct
+{
+  pattern_offset_t begalt_offset;
+  pattern_offset_t fixup_alt_jump;
+  pattern_offset_t inner_group_offset;
+  pattern_offset_t laststart_offset;
+  regnum_t regnum;
+} compile_stack_elt_t;
+
+
+typedef struct
+{
+  compile_stack_elt_t *stack;
+  unsigned size;
+  unsigned avail;			/* Offset of next open position.  */
+} compile_stack_type;
+
+
+#define INIT_COMPILE_STACK_SIZE 32
+
+#define COMPILE_STACK_EMPTY  (compile_stack.avail == 0)
+#define COMPILE_STACK_FULL  (compile_stack.avail == compile_stack.size)
+
+/* The next available element.  */
+#define COMPILE_STACK_TOP (compile_stack.stack[compile_stack.avail])
+
+
+/* Set the bit for character C in a list.  */
+#define SET_LIST_BIT(c)                               \
+  (b[((unsigned char) (c)) / BYTEWIDTH]               \
+   |= 1 << (((unsigned char) c) % BYTEWIDTH))
+
+
+/* Get the next unsigned number in the uncompiled pattern.  */
+#define GET_UNSIGNED_NUMBER(num) 					\
+  { if (p != pend)							\
+     {									\
+       PATFETCH (c); 							\
+       while (ISDIGIT (c)) 						\
+	 { 								\
+	   if (num < 0)							\
+	      num = 0;							\
+	   num = num * 10 + c - '0'; 					\
+	   if (p == pend) 						\
+	      break; 							\
+	   PATFETCH (c);						\
+	 } 								\
+       } 								\
+    }
+
+#define CHAR_CLASS_MAX_LENGTH  6 /* Namely, `xdigit'.  */
+
+#define IS_CHAR_CLASS(string)						\
+   (STREQ (string, "alpha") || STREQ (string, "upper")			\
+    || STREQ (string, "lower") || STREQ (string, "digit")		\
+    || STREQ (string, "alnum") || STREQ (string, "xdigit")		\
+    || STREQ (string, "space") || STREQ (string, "print")		\
+    || STREQ (string, "punct") || STREQ (string, "graph")		\
+    || STREQ (string, "cntrl") || STREQ (string, "blank"))
+
+/* `regex_compile' compiles PATTERN (of length SIZE) according to SYNTAX.
+   Returns one of error codes defined in `regex.h', or zero for success.
+
+   Assumes the `allocated' (and perhaps `buffer') and `translate'
+   fields are set in BUFP on entry.
+
+   If it succeeds, results are put in BUFP (if it returns an error, the
+   contents of BUFP are undefined):
+     `buffer' is the compiled pattern;
+     `syntax' is set to SYNTAX;
+     `used' is set to the length of the compiled pattern;
+     `fastmap_accurate' is zero;
+     `re_nsub' is the number of subexpressions in PATTERN;
+     `not_bol' and `not_eol' are zero;
+
+   The `fastmap' and `newline_anchor' fields are neither
+   examined nor set.  */
+
+static reg_errcode_t
+regex_compile (pattern, size, syntax, bufp)
+     const char *pattern;
+     int size;
+     reg_syntax_t syntax;
+     struct re_pattern_buffer *bufp;
+{
+  /* We fetch characters from PATTERN here.  Even though PATTERN is
+     `char *' (i.e., signed), we declare these variables as unsigned, so
+     they can be reliably used as array indices.  */
+  register unsigned char c, c1;
+
+  /* A random tempory spot in PATTERN.  */
+  const char *p1;
+
+  /* Points to the end of the buffer, where we should append.  */
+  register unsigned char *b;
+
+  /* Keeps track of unclosed groups.  */
+  compile_stack_type compile_stack;
+
+  /* Points to the current (ending) position in the pattern.  */
+  const char *p = pattern;
+  const char *pend = pattern + size;
+
+  /* How to translate the characters in the pattern.  */
+  char *translate = bufp->translate;
+
+  /* Address of the count-byte of the most recently inserted `exactn'
+     command.  This makes it possible to tell if a new exact-match
+     character can be added to that command or if the character requires
+     a new `exactn' command.  */
+  unsigned char *pending_exact = 0;
+
+  /* Address of start of the most recently finished expression.
+     This tells, e.g., postfix * where to find the start of its
+     operand.  Reset at the beginning of groups and alternatives.  */
+  unsigned char *laststart = 0;
+
+  /* Address of beginning of regexp, or inside of last group.  */
+  unsigned char *begalt;
+
+  /* Place in the uncompiled pattern (i.e., the {) to
+     which to go back if the interval is invalid.  */
+  const char *beg_interval;
+
+  /* Address of the place where a forward jump should go to the end of
+     the containing expression.  Each alternative of an `or' -- except the
+     last -- ends with a forward jump of this sort.  */
+  unsigned char *fixup_alt_jump = 0;
+
+  /* Counts open-groups as they are encountered.  Remembered for the
+     matching close-group on the compile stack, so the same register
+     number is put in the stop_memory as the start_memory.  */
+  regnum_t regnum = 0;
+
+#ifdef DEBUG
+  DEBUG_PRINT1 ("\nCompiling pattern: ");
+  if (debug)
+    {
+      unsigned debug_count;
+
+      for (debug_count = 0; debug_count < size; debug_count++)
+	printchar (pattern[debug_count]);
+      putchar ('\n');
+    }
+#endif /* DEBUG */
+
+  /* Initialize the compile stack.  */
+  compile_stack.stack = TALLOC (INIT_COMPILE_STACK_SIZE, compile_stack_elt_t);
+  if (compile_stack.stack == NULL)
+    return REG_ESPACE;
+
+  compile_stack.size = INIT_COMPILE_STACK_SIZE;
+  compile_stack.avail = 0;
+
+  /* Initialize the pattern buffer.  */
+  bufp->syntax = syntax;
+  bufp->fastmap_accurate = 0;
+  bufp->not_bol = bufp->not_eol = 0;
+
+  /* Set `used' to zero, so that if we return an error, the pattern
+     printer (for debugging) will think there's no pattern.  We reset it
+     at the end.  */
+  bufp->used = 0;
+
+  /* Always count groups, whether or not bufp->no_sub is set.  */
+  bufp->re_nsub = 0;
+
+#if !defined (emacs) && !defined (SYNTAX_TABLE)
+  /* Initialize the syntax table.  */
+   init_syntax_once ();
+#endif
+
+  if (bufp->allocated == 0)
+    {
+      if (bufp->buffer)
+	{ /* If zero allocated, but buffer is non-null, try to realloc
+	     enough space.  This loses if buffer's address is bogus, but
+	     that is the user's responsibility.  */
+	  RETALLOC (bufp->buffer, INIT_BUF_SIZE, unsigned char);
+	}
+      else
+	{ /* Caller did not allocate a buffer.  Do it for them.  */
+	  bufp->buffer = TALLOC (INIT_BUF_SIZE, unsigned char);
+	}
+      if (!bufp->buffer) return REG_ESPACE;
+
+      bufp->allocated = INIT_BUF_SIZE;
+    }
+
+  begalt = b = bufp->buffer;
+
+  /* Loop through the uncompiled pattern until we're at the end.  */
+  while (p != pend)
+    {
+      PATFETCH (c);
+
+      switch (c)
+	{
+	case '^':
+	  {
+	    if (   /* If at start of pattern, it's an operator.  */
+		   p == pattern + 1
+		   /* If context independent, it's an operator.  */
+		|| syntax & RE_CONTEXT_INDEP_ANCHORS
+		   /* Otherwise, depends on what's come before.  */
+		|| at_begline_loc_p (pattern, p, syntax))
+	      BUF_PUSH (begline);
+	    else
+	      goto normal_char;
+	  }
+	  break;
+
+
+	case '$':
+	  {
+	    if (   /* If at end of pattern, it's an operator.  */
+		   p == pend
+		   /* If context independent, it's an operator.  */
+		|| syntax & RE_CONTEXT_INDEP_ANCHORS
+		   /* Otherwise, depends on what's next.  */
+		|| at_endline_loc_p (p, pend, syntax))
+	       BUF_PUSH (endline);
+	     else
+	       goto normal_char;
+	   }
+	   break;
+
+
+	case '+':
+	case '?':
+	  if ((syntax & RE_BK_PLUS_QM)
+	      || (syntax & RE_LIMITED_OPS))
+	    goto normal_char;
+	handle_plus:
+	case '*':
+	  /* If there is no previous pattern... */
+	  if (!laststart)
+	    {
+	      if (syntax & RE_CONTEXT_INVALID_OPS)
+		return REG_BADRPT;
+	      else if (!(syntax & RE_CONTEXT_INDEP_OPS))
+		goto normal_char;
+	    }
+
+	  {
+	    /* Are we optimizing this jump?  */
+	    boolean keep_string_p = false;
+
+	    /* 1 means zero (many) matches is allowed.  */
+	    char zero_times_ok = 0, many_times_ok = 0;
+
+	    /* If there is a sequence of repetition chars, collapse it
+	       down to just one (the right one).  We can't combine
+	       interval operators with these because of, e.g., `a{2}*',
+	       which should only match an even number of `a's.  */
+
+	    for (;;)
+	      {
+		zero_times_ok |= c != '+';
+		many_times_ok |= c != '?';
+
+		if (p == pend)
+		  break;
+
+		PATFETCH (c);
+
+		if (c == '*'
+		    || (!(syntax & RE_BK_PLUS_QM) && (c == '+' || c == '?')))
+		  ;
+
+		else if (syntax & RE_BK_PLUS_QM  &&  c == '\\')
+		  {
+		    if (p == pend) return REG_EESCAPE;
+
+		    PATFETCH (c1);
+		    if (!(c1 == '+' || c1 == '?'))
+		      {
+			PATUNFETCH;
+			PATUNFETCH;
+			break;
+		      }
+
+		    c = c1;
+		  }
+		else
+		  {
+		    PATUNFETCH;
+		    break;
+		  }
+
+		/* If we get here, we found another repeat character.  */
+	       }
+
+	    /* Star, etc. applied to an empty pattern is equivalent
+	       to an empty pattern.  */
+	    if (!laststart)
+	      break;
+
+	    /* Now we know whether or not zero matches is allowed
+	       and also whether or not two or more matches is allowed.  */
+	    if (many_times_ok)
+	      { /* More than one repetition is allowed, so put in at the
+		   end a backward relative jump from `b' to before the next
+		   jump we're going to put in below (which jumps from
+		   laststart to after this jump).
+
+		   But if we are at the `*' in the exact sequence `.*\n',
+		   insert an unconditional jump backwards to the .,
+		   instead of the beginning of the loop.  This way we only
+		   push a failure point once, instead of every time
+		   through the loop.  */
+		assert (p - 1 > pattern);
+
+		/* Allocate the space for the jump.  */
+		GET_BUFFER_SPACE (3);
+
+		/* We know we are not at the first character of the pattern,
+		   because laststart was nonzero.  And we've already
+		   incremented `p', by the way, to be the character after
+		   the `*'.  Do we have to do something analogous here
+		   for null bytes, because of RE_DOT_NOT_NULL?  */
+		if (TRANSLATE (*(p - 2)) == TRANSLATE ('.')
+		    && zero_times_ok
+		    && p < pend && TRANSLATE (*p) == TRANSLATE ('\n')
+		    && !(syntax & RE_DOT_NEWLINE))
+		  { /* We have .*\n.  */
+		    STORE_JUMP (jump, b, laststart);
+		    keep_string_p = true;
+		  }
+		else
+		  /* Anything else.  */
+		  STORE_JUMP (maybe_pop_jump, b, laststart - 3);
+
+		/* We've added more stuff to the buffer.  */
+		b += 3;
+	      }
+
+	    /* On failure, jump from laststart to b + 3, which will be the
+	       end of the buffer after this jump is inserted.  */
+	    GET_BUFFER_SPACE (3);
+	    INSERT_JUMP (keep_string_p ? on_failure_keep_string_jump
+				       : on_failure_jump,
+			 laststart, b + 3);
+	    pending_exact = 0;
+	    b += 3;
+
+	    if (!zero_times_ok)
+	      {
+		/* At least one repetition is required, so insert a
+		   `dummy_failure_jump' before the initial
+		   `on_failure_jump' instruction of the loop. This
+		   effects a skip over that instruction the first time
+		   we hit that loop.  */
+		GET_BUFFER_SPACE (3);
+		INSERT_JUMP (dummy_failure_jump, laststart, laststart + 6);
+		b += 3;
+	      }
+	    }
+	  break;
+
+
+	case '.':
+	  laststart = b;
+	  BUF_PUSH (anychar);
+	  break;
+
+
+	case '[':
+	  {
+	    boolean had_char_class = false;
+
+	    if (p == pend) return REG_EBRACK;
+
+	    /* Ensure that we have enough space to push a charset: the
+	       opcode, the length count, and the bitset; 34 bytes in all.  */
+	    GET_BUFFER_SPACE (34);
+
+	    laststart = b;
+
+	    /* We test `*p == '^' twice, instead of using an if
+	       statement, so we only need one BUF_PUSH.  */
+	    BUF_PUSH (*p == '^' ? charset_not : charset);
+	    if (*p == '^')
+	      p++;
+
+	    /* Remember the first position in the bracket expression.  */
+	    p1 = p;
+
+	    /* Push the number of bytes in the bitmap.  */
+	    BUF_PUSH ((1 << BYTEWIDTH) / BYTEWIDTH);
+
+	    /* Clear the whole map.  */
+	    bzero (b, (1 << BYTEWIDTH) / BYTEWIDTH);
+
+	    /* charset_not matches newline according to a syntax bit.  */
+	    if ((re_opcode_t) b[-2] == charset_not
+		&& (syntax & RE_HAT_LISTS_NOT_NEWLINE))
+	      SET_LIST_BIT ('\n');
+
+	    /* Read in characters and ranges, setting map bits.  */
+	    for (;;)
+	      {
+		if (p == pend) return REG_EBRACK;
+
+		PATFETCH (c);
+
+		/* \ might escape characters inside [...] and [^...].  */
+		if ((syntax & RE_BACKSLASH_ESCAPE_IN_LISTS) && c == '\\')
+		  {
+		    if (p == pend) return REG_EESCAPE;
+
+		    PATFETCH (c1);
+		    SET_LIST_BIT (c1);
+		    continue;
+		  }
+
+		/* Could be the end of the bracket expression.  If it's
+		   not (i.e., when the bracket expression is `[]' so
+		   far), the ']' character bit gets set way below.  */
+		if (c == ']' && p != p1 + 1)
+		  break;
+
+		/* Look ahead to see if it's a range when the last thing
+		   was a character class.  */
+		if (had_char_class && c == '-' && *p != ']')
+		  return REG_ERANGE;
+
+		/* Look ahead to see if it's a range when the last thing
+		   was a character: if this is a hyphen not at the
+		   beginning or the end of a list, then it's the range
+		   operator.  */
+		if (c == '-'
+		    && !(p - 2 >= pattern && p[-2] == '[')
+		    && !(p - 3 >= pattern && p[-3] == '[' && p[-2] == '^')
+		    && *p != ']')
+		  {
+		    reg_errcode_t ret
+		      = compile_range (&p, pend, translate, syntax, b);
+		    if (ret != REG_NOERROR) return ret;
+		  }
+
+		else if (p[0] == '-' && p[1] != ']')
+		  { /* This handles ranges made up of characters only.  */
+		    reg_errcode_t ret;
+
+		    /* Move past the `-'.  */
+		    PATFETCH (c1);
+
+		    ret = compile_range (&p, pend, translate, syntax, b);
+		    if (ret != REG_NOERROR) return ret;
+		  }
+
+		/* See if we're at the beginning of a possible character
+		   class.  */
+
+		else if (syntax & RE_CHAR_CLASSES && c == '[' && *p == ':')
+		  { /* Leave room for the null.  */
+		    char str[CHAR_CLASS_MAX_LENGTH + 1];
+
+		    PATFETCH (c);
+		    c1 = 0;
+
+		    /* If pattern is `[[:'.  */
+		    if (p == pend) return REG_EBRACK;
+
+		    for (;;)
+		      {
+			PATFETCH (c);
+			if (c == ':' || c == ']' || p == pend
+			    || c1 == CHAR_CLASS_MAX_LENGTH)
+			  break;
+			str[c1++] = c;
+		      }
+		    str[c1] = '\0';
+
+		    /* If isn't a word bracketed by `[:' and:`]':
+		       undo the ending character, the letters, and leave
+		       the leading `:' and `[' (but set bits for them).  */
+		    if (c == ':' && *p == ']')
+		      {
+			int ch;
+			boolean is_alnum = STREQ (str, "alnum");
+			boolean is_alpha = STREQ (str, "alpha");
+			boolean is_blank = STREQ (str, "blank");
+			boolean is_cntrl = STREQ (str, "cntrl");
+			boolean is_digit = STREQ (str, "digit");
+			boolean is_graph = STREQ (str, "graph");
+			boolean is_lower = STREQ (str, "lower");
+			boolean is_print = STREQ (str, "print");
+			boolean is_punct = STREQ (str, "punct");
+			boolean is_space = STREQ (str, "space");
+			boolean is_upper = STREQ (str, "upper");
+			boolean is_xdigit = STREQ (str, "xdigit");
+
+			if (!IS_CHAR_CLASS (str)) return REG_ECTYPE;
+
+			/* Throw away the ] at the end of the character
+			   class.  */
+			PATFETCH (c);
+
+			if (p == pend) return REG_EBRACK;
+
+			for (ch = 0; ch < 1 << BYTEWIDTH; ch++)
+			  {
+			    if (   (is_alnum  && ISALNUM (ch))
+				|| (is_alpha  && ISALPHA (ch))
+				|| (is_blank  && ISBLANK (ch))
+				|| (is_cntrl  && ISCNTRL (ch))
+				|| (is_digit  && ISDIGIT (ch))
+				|| (is_graph  && ISGRAPH (ch))
+				|| (is_lower  && ISLOWER (ch))
+				|| (is_print  && ISPRINT (ch))
+				|| (is_punct  && ISPUNCT (ch))
+				|| (is_space  && ISSPACE (ch))
+				|| (is_upper  && ISUPPER (ch))
+				|| (is_xdigit && ISXDIGIT (ch)))
+			    SET_LIST_BIT (ch);
+			  }
+			had_char_class = true;
+		      }
+		    else
+		      {
+			c1++;
+			while (c1--)
+			  PATUNFETCH;
+			SET_LIST_BIT ('[');
+			SET_LIST_BIT (':');
+			had_char_class = false;
+		      }
+		  }
+		else
+		  {
+		    had_char_class = false;
+		    SET_LIST_BIT (c);
+		  }
+	      }
+
+	    /* Discard any (non)matching list bytes that are all 0 at the
+	       end of the map.  Decrease the map-length byte too.  */
+	    while ((int) b[-1] > 0 && b[b[-1] - 1] == 0)
+	      b[-1]--;
+	    b += b[-1];
+	  }
+	  break;
+
+
+	case '(':
+	  if (syntax & RE_NO_BK_PARENS)
+	    goto handle_open;
+	  else
+	    goto normal_char;
+
+
+	case ')':
+	  if (syntax & RE_NO_BK_PARENS)
+	    goto handle_close;
+	  else
+	    goto normal_char;
+
+
+	case '\n':
+	  if (syntax & RE_NEWLINE_ALT)
+	    goto handle_alt;
+	  else
+	    goto normal_char;
+
+
+	case '|':
+	  if (syntax & RE_NO_BK_VBAR)
+	    goto handle_alt;
+	  else
+	    goto normal_char;
+
+
+	case '{':
+	   if (syntax & RE_INTERVALS && syntax & RE_NO_BK_BRACES)
+	     goto handle_interval;
+	   else
+	     goto normal_char;
+
+
+	case '\\':
+	  if (p == pend) return REG_EESCAPE;
+
+	  /* Do not translate the character after the \, so that we can
+	     distinguish, e.g., \B from \b, even if we normally would
+	     translate, e.g., B to b.  */
+	  PATFETCH_RAW (c);
+
+	  switch (c)
+	    {
+	    case '(':
+	      if (syntax & RE_NO_BK_PARENS)
+		goto normal_backslash;
+
+	    handle_open:
+	      bufp->re_nsub++;
+	      regnum++;
+
+	      if (COMPILE_STACK_FULL)
+		{
+		  RETALLOC (compile_stack.stack, compile_stack.size << 1,
+			    compile_stack_elt_t);
+		  if (compile_stack.stack == NULL) return REG_ESPACE;
+
+		  compile_stack.size <<= 1;
+		}
+
+	      /* These are the values to restore when we hit end of this
+		 group.  They are all relative offsets, so that if the
+		 whole pattern moves because of realloc, they will still
+		 be valid.  */
+	      COMPILE_STACK_TOP.begalt_offset = begalt - bufp->buffer;
+	      COMPILE_STACK_TOP.fixup_alt_jump
+		= fixup_alt_jump ? fixup_alt_jump - bufp->buffer + 1 : 0;
+	      COMPILE_STACK_TOP.laststart_offset = b - bufp->buffer;
+	      COMPILE_STACK_TOP.regnum = regnum;
+
+	      /* We will eventually replace the 0 with the number of
+		 groups inner to this one.  But do not push a
+		 start_memory for groups beyond the last one we can
+		 represent in the compiled pattern.  */
+	      if (regnum <= MAX_REGNUM)
+		{
+		  COMPILE_STACK_TOP.inner_group_offset = b - bufp->buffer + 2;
+		  BUF_PUSH_3 (start_memory, regnum, 0);
+		}
+
+	      compile_stack.avail++;
+
+	      fixup_alt_jump = 0;
+	      laststart = 0;
+	      begalt = b;
+	      /* If we've reached MAX_REGNUM groups, then this open
+		 won't actually generate any code, so we'll have to
+		 clear pending_exact explicitly.  */
+	      pending_exact = 0;
+	      break;
+
+
+	    case ')':
+	      if (syntax & RE_NO_BK_PARENS) goto normal_backslash;
+
+	      if (COMPILE_STACK_EMPTY)
+	      {
+		if (syntax & RE_UNMATCHED_RIGHT_PAREN_ORD)
+		  goto normal_backslash;
+		else
+		  return REG_ERPAREN;
+	      }
+
+	    handle_close:
+	      if (fixup_alt_jump)
+		{ /* Push a dummy failure point at the end of the
+		     alternative for a possible future
+		     `pop_failure_jump' to pop.  See comments at
+		     `push_dummy_failure' in `re_match_2'.  */
+		  BUF_PUSH (push_dummy_failure);
+
+		  /* We allocated space for this jump when we assigned
+		     to `fixup_alt_jump', in the `handle_alt' case below.  */
+		  STORE_JUMP (jump_past_alt, fixup_alt_jump, b - 1);
+		}
+
+	      /* See similar code for backslashed left paren above.  */
+	      if (COMPILE_STACK_EMPTY)
+	      {
+		if (syntax & RE_UNMATCHED_RIGHT_PAREN_ORD)
+		  goto normal_char;
+		else
+		  return REG_ERPAREN;
+	      }
+
+	      /* Since we just checked for an empty stack above, this
+		 ``can't happen''.  */
+	      assert (compile_stack.avail != 0);
+	      {
+		/* We don't just want to restore into `regnum', because
+		   later groups should continue to be numbered higher,
+		   as in `(ab)c(de)' -- the second group is #2.  */
+		regnum_t this_group_regnum;
+
+		compile_stack.avail--;
+		begalt = bufp->buffer + COMPILE_STACK_TOP.begalt_offset;
+		fixup_alt_jump
+		  = COMPILE_STACK_TOP.fixup_alt_jump
+		    ? bufp->buffer + COMPILE_STACK_TOP.fixup_alt_jump - 1
+		    : 0;
+		laststart = bufp->buffer + COMPILE_STACK_TOP.laststart_offset;
+		this_group_regnum = COMPILE_STACK_TOP.regnum;
+		/* If we've reached MAX_REGNUM groups, then this open
+		   won't actually generate any code, so we'll have to
+		   clear pending_exact explicitly.  */
+		pending_exact = 0;
+
+		/* We're at the end of the group, so now we know how many
+		   groups were inside this one.  */
+		if (this_group_regnum <= MAX_REGNUM)
+		  {
+		    unsigned char *inner_group_loc
+		      = bufp->buffer + COMPILE_STACK_TOP.inner_group_offset;
+
+		    *inner_group_loc = regnum - this_group_regnum;
+		    BUF_PUSH_3 (stop_memory, this_group_regnum,
+				regnum - this_group_regnum);
+		  }
+	      }
+	      break;
+
+
+	    case '|':					/* `\|'.  */
+	      if (syntax & RE_LIMITED_OPS || syntax & RE_NO_BK_VBAR)
+		goto normal_backslash;
+	    handle_alt:
+	      if (syntax & RE_LIMITED_OPS)
+		goto normal_char;
+
+	      /* Insert before the previous alternative a jump which
+		 jumps to this alternative if the former fails.  */
+	      GET_BUFFER_SPACE (3);
+	      INSERT_JUMP (on_failure_jump, begalt, b + 6);
+	      pending_exact = 0;
+	      b += 3;
+
+	      /* The alternative before this one has a jump after it
+		 which gets executed if it gets matched.  Adjust that
+		 jump so it will jump to this alternative's analogous
+		 jump (put in below, which in turn will jump to the next
+		 (if any) alternative's such jump, etc.).  The last such
+		 jump jumps to the correct final destination.  A picture:
+			  _____ _____
+			  |   | |   |
+			  |   v |   v
+			 a | b   | c
+
+		 If we are at `b', then fixup_alt_jump right now points to a
+		 three-byte space after `a'.  We'll put in the jump, set
+		 fixup_alt_jump to right after `b', and leave behind three
+		 bytes which we'll fill in when we get to after `c'.  */
+
+	      if (fixup_alt_jump)
+		STORE_JUMP (jump_past_alt, fixup_alt_jump, b);
+
+	      /* Mark and leave space for a jump after this alternative,
+		 to be filled in later either by next alternative or
+		 when know we're at the end of a series of alternatives.  */
+	      fixup_alt_jump = b;
+	      GET_BUFFER_SPACE (3);
+	      b += 3;
+
+	      laststart = 0;
+	      begalt = b;
+	      break;
+
+
+	    case '{':
+	      /* If \{ is a literal.  */
+	      if (!(syntax & RE_INTERVALS)
+		     /* If we're at `\{' and it's not the open-interval
+			operator.  */
+		  || ((syntax & RE_INTERVALS) && (syntax & RE_NO_BK_BRACES))
+		  || (p - 2 == pattern  &&  p == pend))
+		goto normal_backslash;
+
+	    handle_interval:
+	      {
+		/* If got here, then the syntax allows intervals.  */
+
+		/* At least (most) this many matches must be made.  */
+		int lower_bound = -1, upper_bound = -1;
+
+		beg_interval = p - 1;
+
+		if (p == pend)
+		  {
+		    if (syntax & RE_NO_BK_BRACES)
+		      goto unfetch_interval;
+		    else
+		      return REG_EBRACE;
+		  }
+
+		GET_UNSIGNED_NUMBER (lower_bound);
+
+		if (c == ',')
+		  {
+		    GET_UNSIGNED_NUMBER (upper_bound);
+		    if (upper_bound < 0) upper_bound = RE_DUP_MAX;
+		  }
+		else
+		  /* Interval such as `{1}' => match exactly once. */
+		  upper_bound = lower_bound;
+
+		if (lower_bound < 0 || upper_bound > RE_DUP_MAX
+		    || lower_bound > upper_bound)
+		  {
+		    if (syntax & RE_NO_BK_BRACES)
+		      goto unfetch_interval;
+		    else
+		      return REG_BADBR;
+		  }
+
+		if (!(syntax & RE_NO_BK_BRACES))
+		  {
+		    if (c != '\\') return REG_EBRACE;
+
+		    PATFETCH (c);
+		  }
+
+		if (c != '}')
+		  {
+		    if (syntax & RE_NO_BK_BRACES)
+		      goto unfetch_interval;
+		    else
+		      return REG_BADBR;
+		  }
+
+		/* We just parsed a valid interval.  */
+
+		/* If it's invalid to have no preceding re.  */
+		if (!laststart)
+		  {
+		    if (syntax & RE_CONTEXT_INVALID_OPS)
+		      return REG_BADRPT;
+		    else if (syntax & RE_CONTEXT_INDEP_OPS)
+		      laststart = b;
+		    else
+		      goto unfetch_interval;
+		  }
+
+		/* If the upper bound is zero, don't want to succeed at
+		   all; jump from `laststart' to `b + 3', which will be
+		   the end of the buffer after we insert the jump.  */
+		 if (upper_bound == 0)
+		   {
+		     GET_BUFFER_SPACE (3);
+		     INSERT_JUMP (jump, laststart, b + 3);
+		     b += 3;
+		   }
+
+		 /* Otherwise, we have a nontrivial interval.  When
+		    we're all done, the pattern will look like:
+		      set_number_at <jump count> <upper bound>
+		      set_number_at <succeed_n count> <lower bound>
+		      succeed_n <after jump addr> <succed_n count>
+		      <body of loop>
+		      jump_n <succeed_n addr> <jump count>
+		    (The upper bound and `jump_n' are omitted if
+		    `upper_bound' is 1, though.)  */
+		 else
+		   { /* If the upper bound is > 1, we need to insert
+			more at the end of the loop.  */
+		     unsigned nbytes = 10 + (upper_bound > 1) * 10;
+
+		     GET_BUFFER_SPACE (nbytes);
+
+		     /* Initialize lower bound of the `succeed_n', even
+			though it will be set during matching by its
+			attendant `set_number_at' (inserted next),
+			because `re_compile_fastmap' needs to know.
+			Jump to the `jump_n' we might insert below.  */
+		     INSERT_JUMP2 (succeed_n, laststart,
+				   b + 5 + (upper_bound > 1) * 5,
+				   lower_bound);
+		     b += 5;
+
+		     /* Code to initialize the lower bound.  Insert
+			before the `succeed_n'.  The `5' is the last two
+			bytes of this `set_number_at', plus 3 bytes of
+			the following `succeed_n'.  */
+		     insert_op2 (set_number_at, laststart, 5, lower_bound, b);
+		     b += 5;
+
+		     if (upper_bound > 1)
+		       { /* More than one repetition is allowed, so
+			    append a backward jump to the `succeed_n'
+			    that starts this interval.
+
+			    When we've reached this during matching,
+			    we'll have matched the interval once, so
+			    jump back only `upper_bound - 1' times.  */
+			 STORE_JUMP2 (jump_n, b, laststart + 5,
+				      upper_bound - 1);
+			 b += 5;
+
+			 /* The location we want to set is the second
+			    parameter of the `jump_n'; that is `b-2' as
+			    an absolute address.  `laststart' will be
+			    the `set_number_at' we're about to insert;
+			    `laststart+3' the number to set, the source
+			    for the relative address.  But we are
+			    inserting into the middle of the pattern --
+			    so everything is getting moved up by 5.
+			    Conclusion: (b - 2) - (laststart + 3) + 5,
+			    i.e., b - laststart.
+
+			    We insert this at the beginning of the loop
+			    so that if we fail during matching, we'll
+			    reinitialize the bounds.  */
+			 insert_op2 (set_number_at, laststart, b - laststart,
+				     upper_bound - 1, b);
+			 b += 5;
+		       }
+		   }
+		pending_exact = 0;
+		beg_interval = NULL;
+	      }
+	      break;
+
+	    unfetch_interval:
+	      /* If an invalid interval, match the characters as literals.  */
+	       assert (beg_interval);
+	       p = beg_interval;
+	       beg_interval = NULL;
+
+	       /* normal_char and normal_backslash need `c'.  */
+	       PATFETCH (c);
+
+	       if (!(syntax & RE_NO_BK_BRACES))
+		 {
+		   if (p > pattern  &&  p[-1] == '\\')
+		     goto normal_backslash;
+		 }
+	       goto normal_char;
+
+#ifdef emacs
+	    /* There is no way to specify the before_dot and after_dot
+	       operators.  rms says this is ok.  --karl  */
+	    case '=':
+	      BUF_PUSH (at_dot);
+	      break;
+
+	    case 's':
+	      laststart = b;
+	      PATFETCH (c);
+	      BUF_PUSH_2 (syntaxspec, syntax_spec_code[c]);
+	      break;
+
+	    case 'S':
+	      laststart = b;
+	      PATFETCH (c);
+	      BUF_PUSH_2 (notsyntaxspec, syntax_spec_code[c]);
+	      break;
+#endif /* emacs */
+
+
+	    case 'w':
+	      laststart = b;
+	      BUF_PUSH (wordchar);
+	      break;
+
+
+	    case 'W':
+	      laststart = b;
+	      BUF_PUSH (notwordchar);
+	      break;
+
+
+	    case '<':
+	      BUF_PUSH (wordbeg);
+	      break;
+
+	    case '>':
+	      BUF_PUSH (wordend);
+	      break;
+
+	    case 'b':
+	      BUF_PUSH (wordbound);
+	      break;
+
+	    case 'B':
+	      BUF_PUSH (notwordbound);
+	      break;
+
+	    case '`':
+	      BUF_PUSH (begbuf);
+	      break;
+
+	    case '\'':
+	      BUF_PUSH (endbuf);
+	      break;
+
+	    case '1': case '2': case '3': case '4': case '5':
+	    case '6': case '7': case '8': case '9':
+	      if (syntax & RE_NO_BK_REFS)
+		goto normal_char;
+
+	      c1 = c - '0';
+
+	      if (c1 > regnum)
+		return REG_ESUBREG;
+
+	      /* Can't back reference to a subexpression if inside of it.  */
+	      if (group_in_compile_stack (compile_stack, c1))
+		goto normal_char;
+
+	      laststart = b;
+	      BUF_PUSH_2 (duplicate, c1);
+	      break;
+
+
+	    case '+':
+	    case '?':
+	      if (syntax & RE_BK_PLUS_QM)
+		goto handle_plus;
+	      else
+		goto normal_backslash;
+
+	    default:
+	    normal_backslash:
+	      /* You might think it would be useful for \ to mean
+		 not to translate; but if we don't translate it
+		 it will never match anything.  */
+	      c = TRANSLATE (c);
+	      goto normal_char;
+	    }
+	  break;
+
+
+	default:
+	/* Expects the character in `c'.  */
+	normal_char:
+	      /* If no exactn currently being built.  */
+	  if (!pending_exact
+
+	      /* If last exactn not at current position.  */
+	      || pending_exact + *pending_exact + 1 != b
+
+	      /* We have only one byte following the exactn for the count.  */
+	      || *pending_exact == (1 << BYTEWIDTH) - 1
+
+	      /* If followed by a repetition operator.  */
+	      || *p == '*' || *p == '^'
+	      || ((syntax & RE_BK_PLUS_QM)
+		  ? *p == '\\' && (p[1] == '+' || p[1] == '?')
+		  : (*p == '+' || *p == '?'))
+	      || ((syntax & RE_INTERVALS)
+		  && ((syntax & RE_NO_BK_BRACES)
+		      ? *p == '{'
+		      : (p[0] == '\\' && p[1] == '{'))))
+	    {
+	      /* Start building a new exactn.  */
+
+	      laststart = b;
+
+	      BUF_PUSH_2 (exactn, 0);
+	      pending_exact = b - 1;
+	    }
+
+	  BUF_PUSH (c);
+	  (*pending_exact)++;
+	  break;
+	} /* switch (c) */
+    } /* while p != pend */
+
+
+  /* Through the pattern now.  */
+
+  if (fixup_alt_jump)
+    STORE_JUMP (jump_past_alt, fixup_alt_jump, b);
+
+  if (!COMPILE_STACK_EMPTY)
+    return REG_EPAREN;
+
+  free (compile_stack.stack);
+
+  /* We have succeeded; set the length of the buffer.  */
+  bufp->used = b - bufp->buffer;
+
+#ifdef DEBUG
+  if (debug)
+    {
+      DEBUG_PRINT1 ("\nCompiled pattern: ");
+      print_compiled_pattern (bufp);
+    }
+#endif /* DEBUG */
+
+  return REG_NOERROR;
+} /* regex_compile */
+
+/* Subroutines for `regex_compile'.  */
+
+/* Store OP at LOC followed by two-byte integer parameter ARG.  */
+
+static void
+store_op1 (op, loc, arg)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg;
+{
+  *loc = (unsigned char) op;
+  STORE_NUMBER (loc + 1, arg);
+}
+
+
+/* Like `store_op1', but for two two-byte parameters ARG1 and ARG2.  */
+
+static void
+store_op2 (op, loc, arg1, arg2)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg1, arg2;
+{
+  *loc = (unsigned char) op;
+  STORE_NUMBER (loc + 1, arg1);
+  STORE_NUMBER (loc + 3, arg2);
+}
+
+
+/* Copy the bytes from LOC to END to open up three bytes of space at LOC
+   for OP followed by two-byte integer parameter ARG.  */
+
+static void
+insert_op1 (op, loc, arg, end)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg;
+    unsigned char *end;
+{
+  register unsigned char *pfrom = end;
+  register unsigned char *pto = end + 3;
+
+  while (pfrom != loc)
+    *--pto = *--pfrom;
+
+  store_op1 (op, loc, arg);
+}
+
+
+/* Like `insert_op1', but for two two-byte parameters ARG1 and ARG2.  */
+
+static void
+insert_op2 (op, loc, arg1, arg2, end)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg1, arg2;
+    unsigned char *end;
+{
+  register unsigned char *pfrom = end;
+  register unsigned char *pto = end + 5;
+
+  while (pfrom != loc)
+    *--pto = *--pfrom;
+
+  store_op2 (op, loc, arg1, arg2);
+}
+
+
+/* P points to just after a ^ in PATTERN.  Return true if that ^ comes
+   after an alternative or a begin-subexpression.  We assume there is at
+   least one character before the ^.  */
+
+static boolean
+at_begline_loc_p (pattern, p, syntax)
+    const char *pattern, *p;
+    reg_syntax_t syntax;
+{
+  const char *prev = p - 2;
+  boolean prev_prev_backslash = prev > pattern && prev[-1] == '\\';
+
+  return
+       /* After a subexpression?  */
+       (*prev == '(' && (syntax & RE_NO_BK_PARENS || prev_prev_backslash))
+       /* After an alternative?  */
+    || (*prev == '|' && (syntax & RE_NO_BK_VBAR || prev_prev_backslash));
+}
+
+
+/* The dual of at_begline_loc_p.  This one is for $.  We assume there is
+   at least one character after the $, i.e., `P < PEND'.  */
+
+static boolean
+at_endline_loc_p (p, pend, syntax)
+    const char *p, *pend;
+    int syntax;
+{
+  const char *next = p;
+  boolean next_backslash = *next == '\\';
+  const char *next_next = p + 1 < pend ? p + 1 : NULL;
+
+  return
+       /* Before a subexpression?  */
+       (syntax & RE_NO_BK_PARENS ? *next == ')'
+	: next_backslash && next_next && *next_next == ')')
+       /* Before an alternative?  */
+    || (syntax & RE_NO_BK_VBAR ? *next == '|'
+	: next_backslash && next_next && *next_next == '|');
+}
+
+
+/* Returns true if REGNUM is in one of COMPILE_STACK's elements and
+   false if it's not.  */
+
+static boolean
+group_in_compile_stack (compile_stack, regnum)
+    compile_stack_type compile_stack;
+    regnum_t regnum;
+{
+  int this_element;
+
+  for (this_element = compile_stack.avail - 1;
+       this_element >= 0;
+       this_element--)
+    if (compile_stack.stack[this_element].regnum == regnum)
+      return true;
+
+  return false;
+}
+
+
+/* Read the ending character of a range (in a bracket expression) from the
+   uncompiled pattern *P_PTR (which ends at PEND).  We assume the
+   starting character is in `P[-2]'.  (`P[-1]' is the character `-'.)
+   Then we set the translation of all bits between the starting and
+   ending characters (inclusive) in the compiled pattern B.
+
+   Return an error code.
+
+   We use these short variable names so we can use the same macros as
+   `regex_compile' itself.  */
+
+static reg_errcode_t
+compile_range (p_ptr, pend, translate, syntax, b)
+    const char **p_ptr, *pend;
+    char *translate;
+    reg_syntax_t syntax;
+    unsigned char *b;
+{
+  unsigned this_char;
+
+  const char *p = *p_ptr;
+  int range_start, range_end;
+
+  if (p == pend)
+    return REG_ERANGE;
+
+  /* Even though the pattern is a signed `char *', we need to fetch
+     with unsigned char *'s; if the high bit of the pattern character
+     is set, the range endpoints will be negative if we fetch using a
+     signed char *.
+
+     We also want to fetch the endpoints without translating them; the
+     appropriate translation is done in the bit-setting loop below.  */
+  range_start = ((unsigned char *) p)[-2];
+  range_end   = ((unsigned char *) p)[0];
+
+  /* Have to increment the pointer into the pattern string, so the
+     caller isn't still at the ending character.  */
+  (*p_ptr)++;
+
+  /* If the start is after the end, the range is empty.  */
+  if (range_start > range_end)
+    return syntax & RE_NO_EMPTY_RANGES ? REG_ERANGE : REG_NOERROR;
+
+  /* Here we see why `this_char' has to be larger than an `unsigned
+     char' -- the range is inclusive, so if `range_end' == 0xff
+     (assuming 8-bit characters), we would otherwise go into an infinite
+     loop, since all characters <= 0xff.  */
+  for (this_char = range_start; this_char <= range_end; this_char++)
+    {
+      SET_LIST_BIT (TRANSLATE (this_char));
+    }
+
+  return REG_NOERROR;
+}
+
+/* Failure stack declarations and macros; both re_compile_fastmap and
+   re_match_2 use a failure stack.  These have to be macros because of
+   REGEX_ALLOCATE.  */
+
+
+/* Number of failure points for which to initially allocate space
+   when matching.  If this number is exceeded, we allocate more
+   space, so it is not a hard limit.  */
+#ifndef INIT_FAILURE_ALLOC
+#define INIT_FAILURE_ALLOC 5
+#endif
+
+/* Roughly the maximum number of failure points on the stack.  Would be
+   exactly that if always used MAX_FAILURE_SPACE each time we failed.
+   This is a variable only so users of regex can assign to it; we never
+   change it ourselves.  */
+int re_max_failures = 2000;
+
+typedef const unsigned char *fail_stack_elt_t;
+
+typedef struct
+{
+  fail_stack_elt_t *stack;
+  unsigned size;
+  unsigned avail;			/* Offset of next open position.  */
+} fail_stack_type;
+
+#define FAIL_STACK_EMPTY()     (fail_stack.avail == 0)
+#define FAIL_STACK_PTR_EMPTY() (fail_stack_ptr->avail == 0)
+#define FAIL_STACK_FULL()      (fail_stack.avail == fail_stack.size)
+#define FAIL_STACK_TOP()       (fail_stack.stack[fail_stack.avail])
+
+
+/* Initialize `fail_stack'.  Do `return -2' if the alloc fails.  */
+
+#define INIT_FAIL_STACK()						\
+  do {									\
+    fail_stack.stack = (fail_stack_elt_t *)				\
+      REGEX_ALLOCATE (INIT_FAILURE_ALLOC * sizeof (fail_stack_elt_t));	\
+									\
+    if (fail_stack.stack == NULL)					\
+      return -2;							\
+									\
+    fail_stack.size = INIT_FAILURE_ALLOC;				\
+    fail_stack.avail = 0;						\
+  } while (0)
+
+
+/* Double the size of FAIL_STACK, up to approximately `re_max_failures' items.
+
+   Return 1 if succeeds, and 0 if either ran out of memory
+   allocating space for it or it was already too large.
+
+   REGEX_REALLOCATE requires `destination' be declared.   */
+
+#define DOUBLE_FAIL_STACK(fail_stack)					\
+  ((fail_stack).size > re_max_failures * MAX_FAILURE_ITEMS		\
+   ? 0									\
+   : ((fail_stack).stack = (fail_stack_elt_t *)				\
+	REGEX_REALLOCATE ((fail_stack).stack, 				\
+	  (fail_stack).size * sizeof (fail_stack_elt_t),		\
+	  ((fail_stack).size << 1) * sizeof (fail_stack_elt_t)),	\
+									\
+      (fail_stack).stack == NULL					\
+      ? 0								\
+      : ((fail_stack).size <<= 1, 					\
+	 1)))
+
+
+/* Push PATTERN_OP on FAIL_STACK.
+
+   Return 1 if was able to do so and 0 if ran out of memory allocating
+   space to do so.  */
+#define PUSH_PATTERN_OP(pattern_op, fail_stack)				\
+  ((FAIL_STACK_FULL ()							\
+    && !DOUBLE_FAIL_STACK (fail_stack))					\
+    ? 0									\
+    : ((fail_stack).stack[(fail_stack).avail++] = pattern_op,		\
+       1))
+
+/* This pushes an item onto the failure stack.  Must be a four-byte
+   value.  Assumes the variable `fail_stack'.  Probably should only
+   be called from within `PUSH_FAILURE_POINT'.  */
+#define PUSH_FAILURE_ITEM(item)						\
+  fail_stack.stack[fail_stack.avail++] = (fail_stack_elt_t) item
+
+/* The complement operation.  Assumes `fail_stack' is nonempty.  */
+#define POP_FAILURE_ITEM() fail_stack.stack[--fail_stack.avail]
+
+/* Used to omit pushing failure point id's when we're not debugging.  */
+#ifdef DEBUG
+#define DEBUG_PUSH PUSH_FAILURE_ITEM
+#define DEBUG_POP(item_addr) *(item_addr) = POP_FAILURE_ITEM ()
+#else
+#define DEBUG_PUSH(item)
+#define DEBUG_POP(item_addr)
+#endif
+
+
+/* Push the information about the state we will need
+   if we ever fail back to it.
+
+   Requires variables fail_stack, regstart, regend, reg_info, and
+   num_regs be declared.  DOUBLE_FAIL_STACK requires `destination' be
+   declared.
+
+   Does `return FAILURE_CODE' if runs out of memory.  */
+
+#define PUSH_FAILURE_POINT(pattern_place, string_place, failure_code)	\
+  do {									\
+    char *destination;							\
+    /* Must be int, so when we don't save any registers, the arithmetic	\
+       of 0 + -1 isn't done as unsigned.  */				\
+    int this_reg;							\
+									\
+    DEBUG_STATEMENT (failure_id++);					\
+    DEBUG_STATEMENT (nfailure_points_pushed++);				\
+    DEBUG_PRINT2 ("\nPUSH_FAILURE_POINT #%u:\n", failure_id);		\
+    DEBUG_PRINT2 ("  Before push, next avail: %d\n", (fail_stack).avail);\
+    DEBUG_PRINT2 ("                     size: %d\n", (fail_stack).size);\
+									\
+    DEBUG_PRINT2 ("  slots needed: %d\n", NUM_FAILURE_ITEMS);		\
+    DEBUG_PRINT2 ("     available: %d\n", REMAINING_AVAIL_SLOTS);	\
+									\
+    /* Ensure we have enough space allocated for what we will push.  */	\
+    while (REMAINING_AVAIL_SLOTS < NUM_FAILURE_ITEMS)			\
+      {									\
+	if (!DOUBLE_FAIL_STACK (fail_stack))			\
+	  return failure_code;						\
+									\
+	DEBUG_PRINT2 ("\n  Doubled stack; size now: %d\n",		\
+		       (fail_stack).size);				\
+	DEBUG_PRINT2 ("  slots available: %d\n", REMAINING_AVAIL_SLOTS);\
+      }									\
+									\
+    /* Push the info, starting with the registers.  */			\
+    DEBUG_PRINT1 ("\n");						\
+									\
+    for (this_reg = lowest_active_reg; this_reg <= highest_active_reg;	\
+	 this_reg++)							\
+      {									\
+	DEBUG_PRINT2 ("  Pushing reg: %d\n", this_reg);			\
+	DEBUG_STATEMENT (num_regs_pushed++);				\
+									\
+	DEBUG_PRINT2 ("    start: 0x%x\n", regstart[this_reg]);		\
+	PUSH_FAILURE_ITEM (regstart[this_reg]);				\
+									\
+	DEBUG_PRINT2 ("    end: 0x%x\n", regend[this_reg]);		\
+	PUSH_FAILURE_ITEM (regend[this_reg]);				\
+									\
+	DEBUG_PRINT2 ("    info: 0x%x\n      ", reg_info[this_reg]);	\
+	DEBUG_PRINT2 (" match_null=%d",					\
+		      REG_MATCH_NULL_STRING_P (reg_info[this_reg]));	\
+	DEBUG_PRINT2 (" active=%d", IS_ACTIVE (reg_info[this_reg]));	\
+	DEBUG_PRINT2 (" matched_something=%d",				\
+		      MATCHED_SOMETHING (reg_info[this_reg]));		\
+	DEBUG_PRINT2 (" ever_matched=%d",				\
+		      EVER_MATCHED_SOMETHING (reg_info[this_reg]));	\
+	DEBUG_PRINT1 ("\n");						\
+	PUSH_FAILURE_ITEM (reg_info[this_reg].word);			\
+      }									\
+									\
+    DEBUG_PRINT2 ("  Pushing  low active reg: %d\n", lowest_active_reg);\
+    PUSH_FAILURE_ITEM (lowest_active_reg);				\
+									\
+    DEBUG_PRINT2 ("  Pushing high active reg: %d\n", highest_active_reg);\
+    PUSH_FAILURE_ITEM (highest_active_reg);				\
+									\
+    DEBUG_PRINT2 ("  Pushing pattern 0x%x: ", pattern_place);		\
+    DEBUG_PRINT_COMPILED_PATTERN (bufp, pattern_place, pend);		\
+    PUSH_FAILURE_ITEM (pattern_place);					\
+									\
+    DEBUG_PRINT2 ("  Pushing string 0x%x: `", string_place);		\
+    DEBUG_PRINT_DOUBLE_STRING (string_place, string1, size1, string2,   \
+				 size2);				\
+    DEBUG_PRINT1 ("'\n");						\
+    PUSH_FAILURE_ITEM (string_place);					\
+									\
+    DEBUG_PRINT2 ("  Pushing failure id: %u\n", failure_id);		\
+    DEBUG_PUSH (failure_id);						\
+  } while (0)
+
+/* This is the number of items that are pushed and popped on the stack
+   for each register.  */
+#define NUM_REG_ITEMS  3
+
+/* Individual items aside from the registers.  */
+#ifdef DEBUG
+#define NUM_NONREG_ITEMS 5 /* Includes failure point id.  */
+#else
+#define NUM_NONREG_ITEMS 4
+#endif
+
+/* We push at most this many items on the stack.  */
+#define MAX_FAILURE_ITEMS ((num_regs - 1) * NUM_REG_ITEMS + NUM_NONREG_ITEMS)
+
+/* We actually push this many items.  */
+#define NUM_FAILURE_ITEMS						\
+  ((highest_active_reg - lowest_active_reg + 1) * NUM_REG_ITEMS 	\
+    + NUM_NONREG_ITEMS)
+
+/* How many items can still be added to the stack without overflowing it.  */
+#define REMAINING_AVAIL_SLOTS ((fail_stack).size - (fail_stack).avail)
+
+
+/* Pops what PUSH_FAIL_STACK pushes.
+
+   We restore into the parameters, all of which should be lvalues:
+     STR -- the saved data position.
+     PAT -- the saved pattern position.
+     LOW_REG, HIGH_REG -- the highest and lowest active registers.
+     REGSTART, REGEND -- arrays of string positions.
+     REG_INFO -- array of information about each subexpression.
+
+   Also assumes the variables `fail_stack' and (if debugging), `bufp',
+   `pend', `string1', `size1', `string2', and `size2'.  */
+
+#define POP_FAILURE_POINT(str, pat, low_reg, high_reg, regstart, regend, reg_info)\
+{									\
+  DEBUG_STATEMENT (fail_stack_elt_t failure_id;)			\
+  int this_reg;								\
+  const unsigned char *string_temp;					\
+									\
+  assert (!FAIL_STACK_EMPTY ());					\
+									\
+  /* Remove failure points and point to how many regs pushed.  */	\
+  DEBUG_PRINT1 ("POP_FAILURE_POINT:\n");				\
+  DEBUG_PRINT2 ("  Before pop, next avail: %d\n", fail_stack.avail);	\
+  DEBUG_PRINT2 ("                    size: %d\n", fail_stack.size);	\
+									\
+  assert (fail_stack.avail >= NUM_NONREG_ITEMS);			\
+									\
+  DEBUG_POP (&failure_id);						\
+  DEBUG_PRINT2 ("  Popping failure id: %u\n", failure_id);		\
+									\
+  /* If the saved string location is NULL, it came from an		\
+     on_failure_keep_string_jump opcode, and we want to throw away the	\
+     saved NULL, thus retaining our current position in the string.  */	\
+  string_temp = POP_FAILURE_ITEM ();					\
+  if (string_temp != NULL)						\
+    str = (const char *) string_temp;					\
+									\
+  DEBUG_PRINT2 ("  Popping string 0x%x: `", str);			\
+  DEBUG_PRINT_DOUBLE_STRING (str, string1, size1, string2, size2);	\
+  DEBUG_PRINT1 ("'\n");							\
+									\
+  pat = (unsigned char *) POP_FAILURE_ITEM ();				\
+  DEBUG_PRINT2 ("  Popping pattern 0x%x: ", pat);			\
+  DEBUG_PRINT_COMPILED_PATTERN (bufp, pat, pend);			\
+									\
+  /* Restore register info.  */						\
+  high_reg = (unsigned) POP_FAILURE_ITEM ();				\
+  DEBUG_PRINT2 ("  Popping high active reg: %d\n", high_reg);		\
+									\
+  low_reg = (unsigned) POP_FAILURE_ITEM ();				\
+  DEBUG_PRINT2 ("  Popping  low active reg: %d\n", low_reg);		\
+									\
+  for (this_reg = high_reg; this_reg >= low_reg; this_reg--)		\
+    {									\
+      DEBUG_PRINT2 ("    Popping reg: %d\n", this_reg);			\
+									\
+      reg_info[this_reg].word = POP_FAILURE_ITEM ();			\
+      DEBUG_PRINT2 ("      info: 0x%x\n", reg_info[this_reg]);		\
+									\
+      regend[this_reg] = (const char *) POP_FAILURE_ITEM ();		\
+      DEBUG_PRINT2 ("      end: 0x%x\n", regend[this_reg]);		\
+									\
+      regstart[this_reg] = (const char *) POP_FAILURE_ITEM ();		\
+      DEBUG_PRINT2 ("      start: 0x%x\n", regstart[this_reg]);		\
+    }									\
+									\
+  DEBUG_STATEMENT (nfailure_points_popped++);				\
+} /* POP_FAILURE_POINT */
+
+/* re_compile_fastmap computes a ``fastmap'' for the compiled pattern in
+   BUFP.  A fastmap records which of the (1 << BYTEWIDTH) possible
+   characters can start a string that matches the pattern.  This fastmap
+   is used by re_search to skip quickly over impossible starting points.
+
+   The caller must supply the address of a (1 << BYTEWIDTH)-byte data
+   area as BUFP->fastmap.
+
+   We set the `fastmap', `fastmap_accurate', and `can_be_null' fields in
+   the pattern buffer.
+
+   Returns 0 if we succeed, -2 if an internal error.   */
+
+int
+re_compile_fastmap (bufp)
+     struct re_pattern_buffer *bufp;
+{
+  int j, k;
+  fail_stack_type fail_stack;
+#ifndef REGEX_MALLOC
+  char *destination;
+#endif
+  /* We don't push any register information onto the failure stack.  */
+  unsigned num_regs = 0;
+
+  register char *fastmap = bufp->fastmap;
+  unsigned char *pattern = bufp->buffer;
+  unsigned long size = bufp->used;
+  const unsigned char *p = pattern;
+  register unsigned char *pend = pattern + size;
+
+  /* Assume that each path through the pattern can be null until
+     proven otherwise.  We set this false at the bottom of switch
+     statement, to which we get only if a particular path doesn't
+     match the empty string.  */
+  boolean path_can_be_null = true;
+
+  /* We aren't doing a `succeed_n' to begin with.  */
+  boolean succeed_n_p = false;
+
+  assert (fastmap != NULL && p != NULL);
+
+  INIT_FAIL_STACK ();
+  bzero (fastmap, 1 << BYTEWIDTH);  /* Assume nothing's valid.  */
+  bufp->fastmap_accurate = 1;	    /* It will be when we're done.  */
+  bufp->can_be_null = 0;
+
+  while (p != pend || !FAIL_STACK_EMPTY ())
+    {
+      if (p == pend)
+	{
+	  bufp->can_be_null |= path_can_be_null;
+
+	  /* Reset for next path.  */
+	  path_can_be_null = true;
+
+	  p = fail_stack.stack[--fail_stack.avail];
+	}
+
+      /* We should never be about to go beyond the end of the pattern.  */
+      assert (p < pend);
+
+#ifdef SWITCH_ENUM_BUG
+      switch ((int) ((re_opcode_t) *p++))
+#else
+      switch ((re_opcode_t) *p++)
+#endif
+	{
+
+	/* I guess the idea here is to simply not bother with a fastmap
+	   if a backreference is used, since it's too hard to figure out
+	   the fastmap for the corresponding group.  Setting
+	   `can_be_null' stops `re_search_2' from using the fastmap, so
+	   that is all we do.  */
+	case duplicate:
+	  bufp->can_be_null = 1;
+	  return 0;
+
+
+      /* Following are the cases which match a character.  These end
+	 with `break'.  */
+
+	case exactn:
+	  fastmap[p[1]] = 1;
+	  break;
+
+
+	case charset:
+	  for (j = *p++ * BYTEWIDTH - 1; j >= 0; j--)
+	    if (p[j / BYTEWIDTH] & (1 << (j % BYTEWIDTH)))
+	      fastmap[j] = 1;
+	  break;
+
+
+	case charset_not:
+	  /* Chars beyond end of map must be allowed.  */
+	  for (j = *p * BYTEWIDTH; j < (1 << BYTEWIDTH); j++)
+	    fastmap[j] = 1;
+
+	  for (j = *p++ * BYTEWIDTH - 1; j >= 0; j--)
+	    if (!(p[j / BYTEWIDTH] & (1 << (j % BYTEWIDTH))))
+	      fastmap[j] = 1;
+	  break;
+
+
+	case wordchar:
+	  for (j = 0; j < (1 << BYTEWIDTH); j++)
+	    if (SYNTAX (j) == Sword)
+	      fastmap[j] = 1;
+	  break;
+
+
+	case notwordchar:
+	  for (j = 0; j < (1 << BYTEWIDTH); j++)
+	    if (SYNTAX (j) != Sword)
+	      fastmap[j] = 1;
+	  break;
+
+
+	case anychar:
+	  /* `.' matches anything ...  */
+	  for (j = 0; j < (1 << BYTEWIDTH); j++)
+	    fastmap[j] = 1;
+
+	  /* ... except perhaps newline.  */
+	  if (!(bufp->syntax & RE_DOT_NEWLINE))
+	    fastmap['\n'] = 0;
+
+	  /* Return if we have already set `can_be_null'; if we have,
+	     then the fastmap is irrelevant.  Something's wrong here.  */
+	  else if (bufp->can_be_null)
+	    return 0;
+
+	  /* Otherwise, have to check alternative paths.  */
+	  break;
+
+
+#ifdef emacs
+	case syntaxspec:
+	  k = *p++;
+	  for (j = 0; j < (1 << BYTEWIDTH); j++)
+	    if (SYNTAX (j) == (enum syntaxcode) k)
+	      fastmap[j] = 1;
+	  break;
+
+
+	case notsyntaxspec:
+	  k = *p++;
+	  for (j = 0; j < (1 << BYTEWIDTH); j++)
+	    if (SYNTAX (j) != (enum syntaxcode) k)
+	      fastmap[j] = 1;
+	  break;
+
+
+      /* All cases after this match the empty string.  These end with
+	 `continue'.  */
+
+
+	case before_dot:
+	case at_dot:
+	case after_dot:
+	  continue;
+#endif /* not emacs */
+
+
+	case no_op:
+	case begline:
+	case endline:
+	case begbuf:
+	case endbuf:
+	case wordbound:
+	case notwordbound:
+	case wordbeg:
+	case wordend:
+	case push_dummy_failure:
+	  continue;
+
+
+	case jump_n:
+	case pop_failure_jump:
+	case maybe_pop_jump:
+	case jump:
+	case jump_past_alt:
+	case dummy_failure_jump:
+	  EXTRACT_NUMBER_AND_INCR (j, p);
+	  p += j;
+	  if (j > 0)
+	    continue;
+
+	  /* Jump backward implies we just went through the body of a
+	     loop and matched nothing.  Opcode jumped to should be
+	     `on_failure_jump' or `succeed_n'.  Just treat it like an
+	     ordinary jump.  For a * loop, it has pushed its failure
+	     point already; if so, discard that as redundant.  */
+	  if ((re_opcode_t) *p != on_failure_jump
+	      && (re_opcode_t) *p != succeed_n)
+	    continue;
+
+	  p++;
+	  EXTRACT_NUMBER_AND_INCR (j, p);
+	  p += j;
+
+	  /* If what's on the stack is where we are now, pop it.  */
+	  if (!FAIL_STACK_EMPTY ()
+	      && fail_stack.stack[fail_stack.avail - 1] == p)
+	    fail_stack.avail--;
+
+	  continue;
+
+
+	case on_failure_jump:
+	case on_failure_keep_string_jump:
+	handle_on_failure_jump:
+	  EXTRACT_NUMBER_AND_INCR (j, p);
+
+	  /* For some patterns, e.g., `(a?)?', `p+j' here points to the
+	     end of the pattern.  We don't want to push such a point,
+	     since when we restore it above, entering the switch will
+	     increment `p' past the end of the pattern.  We don't need
+	     to push such a point since we obviously won't find any more
+	     fastmap entries beyond `pend'.  Such a pattern can match
+	     the null string, though.  */
+	  if (p + j < pend)
+	    {
+	      if (!PUSH_PATTERN_OP (p + j, fail_stack))
+		return -2;
+	    }
+	  else
+	    bufp->can_be_null = 1;
+
+	  if (succeed_n_p)
+	    {
+	      EXTRACT_NUMBER_AND_INCR (k, p);	/* Skip the n.  */
+	      succeed_n_p = false;
+	    }
+
+	  continue;
+
+
+	case succeed_n:
+	  /* Get to the number of times to succeed.  */
+	  p += 2;
+
+	  /* Increment p past the n for when k != 0.  */
+	  EXTRACT_NUMBER_AND_INCR (k, p);
+	  if (k == 0)
+	    {
+	      p -= 4;
+	      succeed_n_p = true;  /* Spaghetti code alert.  */
+	      goto handle_on_failure_jump;
+	    }
+	  continue;
+
+
+	case set_number_at:
+	  p += 4;
+	  continue;
+
+
+	case start_memory:
+	case stop_memory:
+	  p += 2;
+	  continue;
+
+
+	default:
+	  abort (); /* We have listed all the cases.  */
+	} /* switch *p++ */
+
+      /* Getting here means we have found the possible starting
+	 characters for one path of the pattern -- and that the empty
+	 string does not match.  We need not follow this path further.
+	 Instead, look at the next alternative (remembered on the
+	 stack), or quit if no more.  The test at the top of the loop
+	 does these things.  */
+      path_can_be_null = false;
+      p = pend;
+    } /* while p */
+
+  /* Set `can_be_null' for the last path (also the first path, if the
+     pattern is empty).  */
+  bufp->can_be_null |= path_can_be_null;
+  return 0;
+} /* re_compile_fastmap */
+
+/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
+   ENDS.  Subsequent matches using PATTERN_BUFFER and REGS will use
+   this memory for recording register information.  STARTS and ENDS
+   must be allocated using the malloc library routine, and must each
+   be at least NUM_REGS * sizeof (regoff_t) bytes long.
+
+   If NUM_REGS == 0, then subsequent matches should allocate their own
+   register data.
+
+   Unless this function is called, the first search or match using
+   PATTERN_BUFFER will allocate its own register data, without
+   freeing the old data.  */
+
+void
+re_set_registers (bufp, regs, num_regs, starts, ends)
+    struct re_pattern_buffer *bufp;
+    struct re_registers *regs;
+    unsigned num_regs;
+    regoff_t *starts, *ends;
+{
+  if (num_regs)
+    {
+      bufp->regs_allocated = REGS_REALLOCATE;
+      regs->num_regs = num_regs;
+      regs->start = starts;
+      regs->end = ends;
+    }
+  else
+    {
+      bufp->regs_allocated = REGS_UNALLOCATED;
+      regs->num_regs = 0;
+      regs->start = regs->end = (regoff_t) 0;
+    }
+}
+
+/* Searching routines.  */
+
+/* Like re_search_2, below, but only one string is specified, and
+   doesn't let you say where to stop matching. */
+
+int
+re_search (bufp, string, size, startpos, range, regs)
+     struct re_pattern_buffer *bufp;
+     const char *string;
+     int size, startpos, range;
+     struct re_registers *regs;
+{
+  return re_search_2 (bufp, NULL, 0, string, size, startpos, range,
+		      regs, size);
+}
+
+
+/* Using the compiled pattern in BUFP->buffer, first tries to match the
+   virtual concatenation of STRING1 and STRING2, starting first at index
+   STARTPOS, then at STARTPOS + 1, and so on.
+
+   STRING1 and STRING2 have length SIZE1 and SIZE2, respectively.
+
+   RANGE is how far to scan while trying to match.  RANGE = 0 means try
+   only at STARTPOS; in general, the last start tried is STARTPOS +
+   RANGE.
+
+   In REGS, return the indices of the virtual concatenation of STRING1
+   and STRING2 that matched the entire BUFP->buffer and its contained
+   subexpressions.
+
+   Do not consider matching one past the index STOP in the virtual
+   concatenation of STRING1 and STRING2.
+
+   We return either the position in the strings at which the match was
+   found, -1 if no match, or -2 if error (such as failure
+   stack overflow).  */
+
+int
+re_search_2 (bufp, string1, size1, string2, size2, startpos, range, regs, stop)
+     struct re_pattern_buffer *bufp;
+     const char *string1, *string2;
+     int size1, size2;
+     int startpos;
+     int range;
+     struct re_registers *regs;
+     int stop;
+{
+  int val;
+  register char *fastmap = bufp->fastmap;
+  register char *translate = bufp->translate;
+  int total_size = size1 + size2;
+  int endpos = startpos + range;
+
+  /* Check for out-of-range STARTPOS.  */
+  if (startpos < 0 || startpos > total_size)
+    return -1;
+
+  /* Fix up RANGE if it might eventually take us outside
+     the virtual concatenation of STRING1 and STRING2.  */
+  if (endpos < -1)
+    range = -1 - startpos;
+  else if (endpos > total_size)
+    range = total_size - startpos;
+
+  /* If the search isn't to be a backwards one, don't waste time in a
+     search for a pattern that must be anchored.  */
+  if (bufp->used > 0 && (re_opcode_t) bufp->buffer[0] == begbuf && range > 0)
+    {
+      if (startpos > 0)
+	return -1;
+      else
+	range = 1;
+    }
+
+  /* Update the fastmap now if not correct already.  */
+  if (fastmap && !bufp->fastmap_accurate)
+    if (re_compile_fastmap (bufp) == -2)
+      return -2;
+
+  /* Loop through the string, looking for a place to start matching.  */
+  for (;;)
+    {
+      /* If a fastmap is supplied, skip quickly over characters that
+	 cannot be the start of a match.  If the pattern can match the
+	 null string, however, we don't need to skip characters; we want
+	 the first null string.  */
+      if (fastmap && startpos < total_size && !bufp->can_be_null)
+	{
+	  if (range > 0)	/* Searching forwards.  */
+	    {
+	      register const char *d;
+	      register int lim = 0;
+	      int irange = range;
+
+	      if (startpos < size1 && startpos + range >= size1)
+		lim = range - (size1 - startpos);
+
+	      d = (startpos >= size1 ? string2 - size1 : string1) + startpos;
+
+	      /* Written out as an if-else to avoid testing `translate'
+		 inside the loop.  */
+	      if (translate)
+		while (range > lim
+		       && !fastmap[(unsigned char)
+				   translate[(unsigned char) *d++]])
+		  range--;
+	      else
+		while (range > lim && !fastmap[(unsigned char) *d++])
+		  range--;
+
+	      startpos += irange - range;
+	    }
+	  else				/* Searching backwards.  */
+	    {
+	      register char c = (size1 == 0 || startpos >= size1
+				 ? string2[startpos - size1]
+				 : string1[startpos]);
+
+	      if (!fastmap[(unsigned char) TRANSLATE (c)])
+		goto advance;
+	    }
+	}
+
+      /* If can't match the null string, and that's all we have left, fail.  */
+      if (range >= 0 && startpos == total_size && fastmap
+	  && !bufp->can_be_null)
+	return -1;
+
+      val = re_match_2 (bufp, string1, size1, string2, size2,
+			startpos, regs, stop);
+      if (val >= 0)
+	return startpos;
+
+      if (val == -2)
+	return -2;
+
+    advance:
+      if (!range)
+	break;
+      else if (range > 0)
+	{
+	  range--;
+	  startpos++;
+	}
+      else
+	{
+	  range++;
+	  startpos--;
+	}
+    }
+  return -1;
+} /* re_search_2 */
+
+/* Declarations and macros for re_match_2.  */
+
+static int bcmp_translate ();
+static boolean alt_match_null_string_p (),
+	       common_op_match_null_string_p (),
+	       group_match_null_string_p ();
+
+/* Structure for per-register (a.k.a. per-group) information.
+   This must not be longer than one word, because we push this value
+   onto the failure stack.  Other register information, such as the
+   starting and ending positions (which are addresses), and the list of
+   inner groups (which is a bits list) are maintained in separate
+   variables.
+
+   We are making a (strictly speaking) nonportable assumption here: that
+   the compiler will pack our bit fields into something that fits into
+   the type of `word', i.e., is something that fits into one item on the
+   failure stack.  */
+typedef union
+{
+  fail_stack_elt_t word;
+  struct
+  {
+      /* This field is one if this group can match the empty string,
+	 zero if not.  If not yet determined,  `MATCH_NULL_UNSET_VALUE'.  */
+#define MATCH_NULL_UNSET_VALUE 3
+    unsigned match_null_string_p : 2;
+    unsigned is_active : 1;
+    unsigned matched_something : 1;
+    unsigned ever_matched_something : 1;
+  } bits;
+} register_info_type;
+
+#define REG_MATCH_NULL_STRING_P(R)  ((R).bits.match_null_string_p)
+#define IS_ACTIVE(R)  ((R).bits.is_active)
+#define MATCHED_SOMETHING(R)  ((R).bits.matched_something)
+#define EVER_MATCHED_SOMETHING(R)  ((R).bits.ever_matched_something)
+
+
+/* Call this when have matched a real character; it sets `matched' flags
+   for the subexpressions which we are currently inside.  Also records
+   that those subexprs have matched.  */
+#define SET_REGS_MATCHED()						\
+  do									\
+    {									\
+      unsigned r;							\
+      for (r = lowest_active_reg; r <= highest_active_reg; r++)		\
+	{								\
+	  MATCHED_SOMETHING (reg_info[r])				\
+	    = EVER_MATCHED_SOMETHING (reg_info[r])			\
+	    = 1;							\
+	}								\
+    }									\
+  while (0)
+
+
+/* This converts PTR, a pointer into one of the search strings `string1'
+   and `string2' into an offset from the beginning of that string.  */
+#define POINTER_TO_OFFSET(ptr)						\
+  (FIRST_STRING_P (ptr) ? (ptr) - string1 : (ptr) - string2 + size1)
+
+/* Registers are set to a sentinel when they haven't yet matched.  */
+#define REG_UNSET_VALUE ((char *) -1)
+#define REG_UNSET(e) ((e) == REG_UNSET_VALUE)
+
+
+/* Macros for dealing with the split strings in re_match_2.  */
+
+#define MATCHING_IN_FIRST_STRING  (dend == end_match_1)
+
+/* Call before fetching a character with *d.  This switches over to
+   string2 if necessary.  */
+#define PREFETCH()							\
+  while (d == dend)						    	\
+    {									\
+      /* End of string2 => fail.  */					\
+      if (dend == end_match_2) 						\
+	goto fail;							\
+      /* End of string1 => advance to string2.  */ 			\
+      d = string2;						        \
+      dend = end_match_2;						\
+    }
+
+
+/* Test if at very beginning or at very end of the virtual concatenation
+   of `string1' and `string2'.  If only one string, it's `string2'.  */
+#define AT_STRINGS_BEG(d) ((d) == (size1 ? string1 : string2) || !size2)
+#define AT_STRINGS_END(d) ((d) == end2)
+
+
+/* Test if D points to a character which is word-constituent.  We have
+   two special cases to check for: if past the end of string1, look at
+   the first character in string2; and if before the beginning of
+   string2, look at the last character in string1.  */
+#define WORDCHAR_P(d)							\
+  (SYNTAX ((d) == end1 ? *string2					\
+	   : (d) == string2 - 1 ? *(end1 - 1) : *(d))			\
+   == Sword)
+
+/* Test if the character before D and the one at D differ with respect
+   to being word-constituent.  */
+#define AT_WORD_BOUNDARY(d)						\
+  (AT_STRINGS_BEG (d) || AT_STRINGS_END (d)				\
+   || WORDCHAR_P (d - 1) != WORDCHAR_P (d))
+
+
+/* Free everything we malloc.  */
+#ifdef REGEX_MALLOC
+#define FREE_VAR(var) if (var) free (var); var = NULL
+#define FREE_VARIABLES()						\
+  do {									\
+    FREE_VAR (fail_stack.stack);					\
+    FREE_VAR (regstart);						\
+    FREE_VAR (regend);							\
+    FREE_VAR (old_regstart);						\
+    FREE_VAR (old_regend);						\
+    FREE_VAR (best_regstart);						\
+    FREE_VAR (best_regend);						\
+    FREE_VAR (reg_info);						\
+    FREE_VAR (reg_dummy);						\
+    FREE_VAR (reg_info_dummy);						\
+  } while (0)
+#else /* not REGEX_MALLOC */
+/* Some MIPS systems (at least) want this to free alloca'd storage.  */
+#define FREE_VARIABLES() alloca (0)
+#endif /* not REGEX_MALLOC */
+
+
+/* These values must meet several constraints.  They must not be valid
+   register values; since we have a limit of 255 registers (because
+   we use only one byte in the pattern for the register number), we can
+   use numbers larger than 255.  They must differ by 1, because of
+   NUM_FAILURE_ITEMS above.  And the value for the lowest register must
+   be larger than the value for the highest register, so we do not try
+   to actually save any registers when none are active.  */
+#define NO_HIGHEST_ACTIVE_REG (1 << BYTEWIDTH)
+#define NO_LOWEST_ACTIVE_REG (NO_HIGHEST_ACTIVE_REG + 1)
+
+/* Matching routines.  */
+
+#ifndef emacs   /* Emacs never uses this.  */
+/* re_match is like re_match_2 except it takes only a single string.  */
+
+int
+re_match (bufp, string, size, pos, regs)
+     struct re_pattern_buffer *bufp;
+     const char *string;
+     int size, pos;
+     struct re_registers *regs;
+ {
+  return re_match_2 (bufp, NULL, 0, string, size, pos, regs, size);
+}
+#endif /* not emacs */
+
+
+/* re_match_2 matches the compiled pattern in BUFP against the
+   the (virtual) concatenation of STRING1 and STRING2 (of length SIZE1
+   and SIZE2, respectively).  We start matching at POS, and stop
+   matching at STOP.
+
+   If REGS is non-null and the `no_sub' field of BUFP is nonzero, we
+   store offsets for the substring each group matched in REGS.  See the
+   documentation for exactly how many groups we fill.
+
+   We return -1 if no match, -2 if an internal error (such as the
+   failure stack overflowing).  Otherwise, we return the length of the
+   matched substring.  */
+
+int
+re_match_2 (bufp, string1, size1, string2, size2, pos, regs, stop)
+     struct re_pattern_buffer *bufp;
+     const char *string1, *string2;
+     int size1, size2;
+     int pos;
+     struct re_registers *regs;
+     int stop;
+{
+  /* General temporaries.  */
+  int mcnt;
+  unsigned char *p1;
+
+  /* Just past the end of the corresponding string.  */
+  const char *end1, *end2;
+
+  /* Pointers into string1 and string2, just past the last characters in
+     each to consider matching.  */
+  const char *end_match_1, *end_match_2;
+
+  /* Where we are in the data, and the end of the current string.  */
+  const char *d, *dend;
+
+  /* Where we are in the pattern, and the end of the pattern.  */
+  unsigned char *p = bufp->buffer;
+  register unsigned char *pend = p + bufp->used;
+
+  /* We use this to map every character in the string.  */
+  char *translate = bufp->translate;
+
+  /* Failure point stack.  Each place that can handle a failure further
+     down the line pushes a failure point on this stack.  It consists of
+     restart, regend, and reg_info for all registers corresponding to
+     the subexpressions we're currently inside, plus the number of such
+     registers, and, finally, two char *'s.  The first char * is where
+     to resume scanning the pattern; the second one is where to resume
+     scanning the strings.  If the latter is zero, the failure point is
+     a ``dummy''; if a failure happens and the failure point is a dummy,
+     it gets discarded and the next next one is tried.  */
+  fail_stack_type fail_stack;
+#ifdef DEBUG
+  static unsigned failure_id = 0;
+  unsigned nfailure_points_pushed = 0, nfailure_points_popped = 0;
+#endif
+
+  /* We fill all the registers internally, independent of what we
+     return, for use in backreferences.  The number here includes
+     an element for register zero.  */
+  unsigned num_regs = bufp->re_nsub + 1;
+
+  /* The currently active registers.  */
+  unsigned lowest_active_reg = NO_LOWEST_ACTIVE_REG;
+  unsigned highest_active_reg = NO_HIGHEST_ACTIVE_REG;
+
+  /* Information on the contents of registers. These are pointers into
+     the input strings; they record just what was matched (on this
+     attempt) by a subexpression part of the pattern, that is, the
+     regnum-th regstart pointer points to where in the pattern we began
+     matching and the regnum-th regend points to right after where we
+     stopped matching the regnum-th subexpression.  (The zeroth register
+     keeps track of what the whole pattern matches.)  */
+  const char **regstart = NULL, **regend = NULL;
+
+  /* If a group that's operated upon by a repetition operator fails to
+     match anything, then the register for its start will need to be
+     restored because it will have been set to wherever in the string we
+     are when we last see its open-group operator.  Similarly for a
+     register's end.  */
+  const char **old_regstart = NULL, **old_regend = NULL;
+
+  /* The is_active field of reg_info helps us keep track of which (possibly
+     nested) subexpressions we are currently in. The matched_something
+     field of reg_info[reg_num] helps us tell whether or not we have
+     matched any of the pattern so far this time through the reg_num-th
+     subexpression.  These two fields get reset each time through any
+     loop their register is in.  */
+  register_info_type *reg_info = NULL;
+
+  /* The following record the register info as found in the above
+     variables when we find a match better than any we've seen before.
+     This happens as we backtrack through the failure points, which in
+     turn happens only if we have not yet matched the entire string. */
+  unsigned best_regs_set = false;
+  const char **best_regstart = NULL, **best_regend = NULL;
+
+  /* Logically, this is `best_regend[0]'.  But we don't want to have to
+     allocate space for that if we're not allocating space for anything
+     else (see below).  Also, we never need info about register 0 for
+     any of the other register vectors, and it seems rather a kludge to
+     treat `best_regend' differently than the rest.  So we keep track of
+     the end of the best match so far in a separate variable.  We
+     initialize this to NULL so that when we backtrack the first time
+     and need to test it, it's not garbage.  */
+  const char *match_end = NULL;
+
+  /* Used when we pop values we don't care about.  */
+  const char **reg_dummy = NULL;
+  register_info_type *reg_info_dummy = NULL;
+
+#ifdef DEBUG
+  /* Counts the total number of registers pushed.  */
+  unsigned num_regs_pushed = 0;
+#endif
+
+  DEBUG_PRINT1 ("\n\nEntering re_match_2.\n");
+
+  INIT_FAIL_STACK ();
+
+  /* Do not bother to initialize all the register variables if there are
+     no groups in the pattern, as it takes a fair amount of time.  If
+     there are groups, we include space for register 0 (the whole
+     pattern), even though we never use it, since it simplifies the
+     array indexing.  We should fix this.  */
+  if (bufp->re_nsub)
+    {
+      regstart = REGEX_TALLOC (num_regs, const char *);
+      regend = REGEX_TALLOC (num_regs, const char *);
+      old_regstart = REGEX_TALLOC (num_regs, const char *);
+      old_regend = REGEX_TALLOC (num_regs, const char *);
+      best_regstart = REGEX_TALLOC (num_regs, const char *);
+      best_regend = REGEX_TALLOC (num_regs, const char *);
+      reg_info = REGEX_TALLOC (num_regs, register_info_type);
+      reg_dummy = REGEX_TALLOC (num_regs, const char *);
+      reg_info_dummy = REGEX_TALLOC (num_regs, register_info_type);
+
+      if (!(regstart && regend && old_regstart && old_regend && reg_info
+	    && best_regstart && best_regend && reg_dummy && reg_info_dummy))
+	{
+	  FREE_VARIABLES ();
+	  return -2;
+	}
+    }
+#ifdef REGEX_MALLOC
+  else
+    {
+      /* We must initialize all our variables to NULL, so that
+	 `FREE_VARIABLES' doesn't try to free them.  */
+      regstart = regend = old_regstart = old_regend = best_regstart
+	= best_regend = reg_dummy = NULL;
+      reg_info = reg_info_dummy = (register_info_type *) NULL;
+    }
+#endif /* REGEX_MALLOC */
+
+  /* The starting position is bogus.  */
+  if (pos < 0 || pos > size1 + size2)
+    {
+      FREE_VARIABLES ();
+      return -1;
+    }
+
+  /* Initialize subexpression text positions to -1 to mark ones that no
+     start_memory/stop_memory has been seen for. Also initialize the
+     register information struct.  */
+  for (mcnt = 1; mcnt < num_regs; mcnt++)
+    {
+      regstart[mcnt] = regend[mcnt]
+	= old_regstart[mcnt] = old_regend[mcnt] = REG_UNSET_VALUE;
+
+      REG_MATCH_NULL_STRING_P (reg_info[mcnt]) = MATCH_NULL_UNSET_VALUE;
+      IS_ACTIVE (reg_info[mcnt]) = 0;
+      MATCHED_SOMETHING (reg_info[mcnt]) = 0;
+      EVER_MATCHED_SOMETHING (reg_info[mcnt]) = 0;
+    }
+
+  /* We move `string1' into `string2' if the latter's empty -- but not if
+     `string1' is null.  */
+  if (size2 == 0 && string1 != NULL)
+    {
+      string2 = string1;
+      size2 = size1;
+      string1 = 0;
+      size1 = 0;
+    }
+  end1 = string1 + size1;
+  end2 = string2 + size2;
+
+  /* Compute where to stop matching, within the two strings.  */
+  if (stop <= size1)
+    {
+      end_match_1 = string1 + stop;
+      end_match_2 = string2;
+    }
+  else
+    {
+      end_match_1 = end1;
+      end_match_2 = string2 + stop - size1;
+    }
+
+  /* `p' scans through the pattern as `d' scans through the data.
+     `dend' is the end of the input string that `d' points within.  `d'
+     is advanced into the following input string whenever necessary, but
+     this happens before fetching; therefore, at the beginning of the
+     loop, `d' can be pointing at the end of a string, but it cannot
+     equal `string2'.  */
+  if (size1 > 0 && pos <= size1)
+    {
+      d = string1 + pos;
+      dend = end_match_1;
+    }
+  else
+    {
+      d = string2 + pos - size1;
+      dend = end_match_2;
+    }
+
+  DEBUG_PRINT1 ("The compiled pattern is: ");
+  DEBUG_PRINT_COMPILED_PATTERN (bufp, p, pend);
+  DEBUG_PRINT1 ("The string to match is: `");
+  DEBUG_PRINT_DOUBLE_STRING (d, string1, size1, string2, size2);
+  DEBUG_PRINT1 ("'\n");
+
+  /* This loops over pattern commands.  It exits by returning from the
+     function if the match is complete, or it drops through if the match
+     fails at this starting point in the input data.  */
+  for (;;)
+    {
+      DEBUG_PRINT2 ("\n0x%x: ", p);
+
+      if (p == pend)
+	{ /* End of pattern means we might have succeeded.  */
+	  DEBUG_PRINT1 ("end of pattern ... ");
+
+	  /* If we haven't matched the entire string, and we want the
+	     longest match, try backtracking.  */
+	  if (d != end_match_2)
+	    {
+	      DEBUG_PRINT1 ("backtracking.\n");
+
+	      if (!FAIL_STACK_EMPTY ())
+		{ /* More failure points to try.  */
+		  boolean same_str_p = (FIRST_STRING_P (match_end)
+					== MATCHING_IN_FIRST_STRING);
+
+		  /* If exceeds best match so far, save it.  */
+		  if (!best_regs_set
+		      || (same_str_p && d > match_end)
+		      || (!same_str_p && !MATCHING_IN_FIRST_STRING))
+		    {
+		      best_regs_set = true;
+		      match_end = d;
+
+		      DEBUG_PRINT1 ("\nSAVING match as best so far.\n");
+
+		      for (mcnt = 1; mcnt < num_regs; mcnt++)
+			{
+			  best_regstart[mcnt] = regstart[mcnt];
+			  best_regend[mcnt] = regend[mcnt];
+			}
+		    }
+		  goto fail;
+		}
+
+	      /* If no failure points, don't restore garbage.  */
+	      else if (best_regs_set)
+		{
+		restore_best_regs:
+		  /* Restore best match.  It may happen that `dend ==
+		     end_match_1' while the restored d is in string2.
+		     For example, the pattern `x.*y.*z' against the
+		     strings `x-' and `y-z-', if the two strings are
+		     not consecutive in memory.  */
+		  DEBUG_PRINT1 ("Restoring best registers.\n");
+
+		  d = match_end;
+		  dend = ((d >= string1 && d <= end1)
+			   ? end_match_1 : end_match_2);
+
+		  for (mcnt = 1; mcnt < num_regs; mcnt++)
+		    {
+		      regstart[mcnt] = best_regstart[mcnt];
+		      regend[mcnt] = best_regend[mcnt];
+		    }
+		}
+	    } /* d != end_match_2 */
+
+	  DEBUG_PRINT1 ("Accepting match.\n");
+
+	  /* If caller wants register contents data back, do it.  */
+	  if (regs && !bufp->no_sub)
+	    {
+	      /* Have the register data arrays been allocated?  */
+	      if (bufp->regs_allocated == REGS_UNALLOCATED)
+		{ /* No.  So allocate them with malloc.  We need one
+		     extra element beyond `num_regs' for the `-1' marker
+		     GNU code uses.  */
+		  regs->num_regs = MAX (RE_NREGS, num_regs + 1);
+		  regs->start = TALLOC (regs->num_regs, regoff_t);
+		  regs->end = TALLOC (regs->num_regs, regoff_t);
+		  if (regs->start == NULL || regs->end == NULL)
+		    return -2;
+		  bufp->regs_allocated = REGS_REALLOCATE;
+		}
+	      else if (bufp->regs_allocated == REGS_REALLOCATE)
+		{ /* Yes.  If we need more elements than were already
+		     allocated, reallocate them.  If we need fewer, just
+		     leave it alone.  */
+		  if (regs->num_regs < num_regs + 1)
+		    {
+		      regs->num_regs = num_regs + 1;
+		      RETALLOC (regs->start, regs->num_regs, regoff_t);
+		      RETALLOC (regs->end, regs->num_regs, regoff_t);
+		      if (regs->start == NULL || regs->end == NULL)
+			return -2;
+		    }
+		}
+	      else
+		assert (bufp->regs_allocated == REGS_FIXED);
+
+	      /* Convert the pointer data in `regstart' and `regend' to
+		 indices.  Register zero has to be set differently,
+		 since we haven't kept track of any info for it.  */
+	      if (regs->num_regs > 0)
+		{
+		  regs->start[0] = pos;
+		  regs->end[0] = (MATCHING_IN_FIRST_STRING ? d - string1
+				  : d - string2 + size1);
+		}
+
+	      /* Go through the first `min (num_regs, regs->num_regs)'
+		 registers, since that is all we initialized.  */
+	      for (mcnt = 1; mcnt < MIN (num_regs, regs->num_regs); mcnt++)
+		{
+		  if (REG_UNSET (regstart[mcnt]) || REG_UNSET (regend[mcnt]))
+		    regs->start[mcnt] = regs->end[mcnt] = -1;
+		  else
+		    {
+		      regs->start[mcnt] = POINTER_TO_OFFSET (regstart[mcnt]);
+		      regs->end[mcnt] = POINTER_TO_OFFSET (regend[mcnt]);
+		    }
+		}
+
+	      /* If the regs structure we return has more elements than
+		 were in the pattern, set the extra elements to -1.  If
+		 we (re)allocated the registers, this is the case,
+		 because we always allocate enough to have at least one
+		 -1 at the end.  */
+	      for (mcnt = num_regs; mcnt < regs->num_regs; mcnt++)
+		regs->start[mcnt] = regs->end[mcnt] = -1;
+	    } /* regs && !bufp->no_sub */
+
+	  FREE_VARIABLES ();
+	  DEBUG_PRINT4 ("%u failure points pushed, %u popped (%u remain).\n",
+			nfailure_points_pushed, nfailure_points_popped,
+			nfailure_points_pushed - nfailure_points_popped);
+	  DEBUG_PRINT2 ("%u registers pushed.\n", num_regs_pushed);
+
+	  mcnt = d - pos - (MATCHING_IN_FIRST_STRING
+			    ? string1
+			    : string2 - size1);
+
+	  DEBUG_PRINT2 ("Returning %d from re_match_2.\n", mcnt);
+
+	  return mcnt;
+	}
+
+      /* Otherwise match next pattern command.  */
+#ifdef SWITCH_ENUM_BUG
+      switch ((int) ((re_opcode_t) *p++))
+#else
+      switch ((re_opcode_t) *p++)
+#endif
+	{
+	/* Ignore these.  Used to ignore the n of succeed_n's which
+	   currently have n == 0.  */
+	case no_op:
+	  DEBUG_PRINT1 ("EXECUTING no_op.\n");
+	  break;
+
+
+	/* Match the next n pattern characters exactly.  The following
+	   byte in the pattern defines n, and the n bytes after that
+	   are the characters to match.  */
+	case exactn:
+	  mcnt = *p++;
+	  DEBUG_PRINT2 ("EXECUTING exactn %d.\n", mcnt);
+
+	  /* This is written out as an if-else so we don't waste time
+	     testing `translate' inside the loop.  */
+	  if (translate)
+	    {
+	      do
+		{
+		  PREFETCH ();
+		  if (translate[(unsigned char) *d++] != (char) *p++)
+		    goto fail;
+		}
+	      while (--mcnt);
+	    }
+	  else
+	    {
+	      do
+		{
+		  PREFETCH ();
+		  if (*d++ != (char) *p++) goto fail;
+		}
+	      while (--mcnt);
+	    }
+	  SET_REGS_MATCHED ();
+	  break;
+
+
+	/* Match any character except possibly a newline or a null.  */
+	case anychar:
+	  DEBUG_PRINT1 ("EXECUTING anychar.\n");
+
+	  PREFETCH ();
+
+	  if ((!(bufp->syntax & RE_DOT_NEWLINE) && TRANSLATE (*d) == '\n')
+	      || (bufp->syntax & RE_DOT_NOT_NULL && TRANSLATE (*d) == '\000'))
+	    goto fail;
+
+	  SET_REGS_MATCHED ();
+	  DEBUG_PRINT2 ("  Matched `%d'.\n", *d);
+	  d++;
+	  break;
+
+
+	case charset:
+	case charset_not:
+	  {
+	    register unsigned char c;
+	    boolean not = (re_opcode_t) *(p - 1) == charset_not;
+
+	    DEBUG_PRINT2 ("EXECUTING charset%s.\n", not ? "_not" : "");
+
+	    PREFETCH ();
+	    c = TRANSLATE (*d); /* The character to match.  */
+
+	    /* Cast to `unsigned' instead of `unsigned char' in case the
+	       bit list is a full 32 bytes long.  */
+	    if (c < (unsigned) (*p * BYTEWIDTH)
+		&& p[1 + c / BYTEWIDTH] & (1 << (c % BYTEWIDTH)))
+	      not = !not;
+
+	    p += 1 + *p;
+
+	    if (!not) goto fail;
+
+	    SET_REGS_MATCHED ();
+	    d++;
+	    break;
+	  }
+
+
+	/* The beginning of a group is represented by start_memory.
+	   The arguments are the register number in the next byte, and the
+	   number of groups inner to this one in the next.  The text
+	   matched within the group is recorded (in the internal
+	   registers data structure) under the register number.  */
+	case start_memory:
+	  DEBUG_PRINT3 ("EXECUTING start_memory %d (%d):\n", *p, p[1]);
+
+	  /* Find out if this group can match the empty string.  */
+	  p1 = p;		/* To send to group_match_null_string_p.  */
+
+	  if (REG_MATCH_NULL_STRING_P (reg_info[*p]) == MATCH_NULL_UNSET_VALUE)
+	    REG_MATCH_NULL_STRING_P (reg_info[*p])
+	      = group_match_null_string_p (&p1, pend, reg_info);
+
+	  /* Save the position in the string where we were the last time
+	     we were at this open-group operator in case the group is
+	     operated upon by a repetition operator, e.g., with `(a*)*b'
+	     against `ab'; then we want to ignore where we are now in
+	     the string in case this attempt to match fails.  */
+	  old_regstart[*p] = REG_MATCH_NULL_STRING_P (reg_info[*p])
+			     ? REG_UNSET (regstart[*p]) ? d : regstart[*p]
+			     : regstart[*p];
+	  DEBUG_PRINT2 ("  old_regstart: %d\n",
+			 POINTER_TO_OFFSET (old_regstart[*p]));
+
+	  regstart[*p] = d;
+	  DEBUG_PRINT2 ("  regstart: %d\n", POINTER_TO_OFFSET (regstart[*p]));
+
+	  IS_ACTIVE (reg_info[*p]) = 1;
+	  MATCHED_SOMETHING (reg_info[*p]) = 0;
+
+	  /* This is the new highest active register.  */
+	  highest_active_reg = *p;
+
+	  /* If nothing was active before, this is the new lowest active
+	     register.  */
+	  if (lowest_active_reg == NO_LOWEST_ACTIVE_REG)
+	    lowest_active_reg = *p;
+
+	  /* Move past the register number and inner group count.  */
+	  p += 2;
+	  break;
+
+
+	/* The stop_memory opcode represents the end of a group.  Its
+	   arguments are the same as start_memory's: the register
+	   number, and the number of inner groups.  */
+	case stop_memory:
+	  DEBUG_PRINT3 ("EXECUTING stop_memory %d (%d):\n", *p, p[1]);
+
+	  /* We need to save the string position the last time we were at
+	     this close-group operator in case the group is operated
+	     upon by a repetition operator, e.g., with `((a*)*(b*)*)*'
+	     against `aba'; then we want to ignore where we are now in
+	     the string in case this attempt to match fails.  */
+	  old_regend[*p] = REG_MATCH_NULL_STRING_P (reg_info[*p])
+			   ? REG_UNSET (regend[*p]) ? d : regend[*p]
+			   : regend[*p];
+	  DEBUG_PRINT2 ("      old_regend: %d\n",
+			 POINTER_TO_OFFSET (old_regend[*p]));
+
+	  regend[*p] = d;
+	  DEBUG_PRINT2 ("      regend: %d\n", POINTER_TO_OFFSET (regend[*p]));
+
+	  /* This register isn't active anymore.  */
+	  IS_ACTIVE (reg_info[*p]) = 0;
+
+	  /* If this was the only register active, nothing is active
+	     anymore.  */
+	  if (lowest_active_reg == highest_active_reg)
+	    {
+	      lowest_active_reg = NO_LOWEST_ACTIVE_REG;
+	      highest_active_reg = NO_HIGHEST_ACTIVE_REG;
+	    }
+	  else
+	    { /* We must scan for the new highest active register, since
+		 it isn't necessarily one less than now: consider
+		 (a(b)c(d(e)f)g).  When group 3 ends, after the f), the
+		 new highest active register is 1.  */
+	      unsigned char r = *p - 1;
+	      while (r > 0 && !IS_ACTIVE (reg_info[r]))
+		r--;
+
+	      /* If we end up at register zero, that means that we saved
+		 the registers as the result of an `on_failure_jump', not
+		 a `start_memory', and we jumped to past the innermost
+		 `stop_memory'.  For example, in ((.)*) we save
+		 registers 1 and 2 as a result of the *, but when we pop
+		 back to the second ), we are at the stop_memory 1.
+		 Thus, nothing is active.  */
+	      if (r == 0)
+		{
+		  lowest_active_reg = NO_LOWEST_ACTIVE_REG;
+		  highest_active_reg = NO_HIGHEST_ACTIVE_REG;
+		}
+	      else
+		highest_active_reg = r;
+	    }
+
+	  /* If just failed to match something this time around with a
+	     group that's operated on by a repetition operator, try to
+	     force exit from the ``loop'', and restore the register
+	     information for this group that we had before trying this
+	     last match.  */
+	  if ((!MATCHED_SOMETHING (reg_info[*p])
+	       || (re_opcode_t) p[-3] == start_memory)
+	      && (p + 2) < pend)
+	    {
+	      boolean is_a_jump_n = false;
+
+	      p1 = p + 2;
+	      mcnt = 0;
+	      switch ((re_opcode_t) *p1++)
+		{
+		  case jump_n:
+		    is_a_jump_n = true;
+		  case pop_failure_jump:
+		  case maybe_pop_jump:
+		  case jump:
+		  case dummy_failure_jump:
+		    EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+		    if (is_a_jump_n)
+		      p1 += 2;
+		    break;
+
+		  default:
+		    /* do nothing */ ;
+		}
+	      p1 += mcnt;
+
+	      /* If the next operation is a jump backwards in the pattern
+		 to an on_failure_jump right before the start_memory
+		 corresponding to this stop_memory, exit from the loop
+		 by forcing a failure after pushing on the stack the
+		 on_failure_jump's jump in the pattern, and d.  */
+	      if (mcnt < 0 && (re_opcode_t) *p1 == on_failure_jump
+		  && (re_opcode_t) p1[3] == start_memory && p1[4] == *p)
+		{
+		  /* If this group ever matched anything, then restore
+		     what its registers were before trying this last
+		     failed match, e.g., with `(a*)*b' against `ab' for
+		     regstart[1], and, e.g., with `((a*)*(b*)*)*'
+		     against `aba' for regend[3].
+
+		     Also restore the registers for inner groups for,
+		     e.g., `((a*)(b*))*' against `aba' (register 3 would
+		     otherwise get trashed).  */
+
+		  if (EVER_MATCHED_SOMETHING (reg_info[*p]))
+		    {
+		      unsigned r;
+
+		      EVER_MATCHED_SOMETHING (reg_info[*p]) = 0;
+
+		      /* Restore this and inner groups' (if any) registers.  */
+		      for (r = *p; r < *p + *(p + 1); r++)
+			{
+			  regstart[r] = old_regstart[r];
+
+			  /* xx why this test?  */
+			  if ((int) old_regend[r] >= (int) regstart[r])
+			    regend[r] = old_regend[r];
+			}
+		    }
+		  p1++;
+		  EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+		  PUSH_FAILURE_POINT (p1 + mcnt, d, -2);
+
+		  goto fail;
+		}
+	    }
+
+	  /* Move past the register number and the inner group count.  */
+	  p += 2;
+	  break;
+
+
+	/* \<digit> has been turned into a `duplicate' command which is
+	   followed by the numeric value of <digit> as the register number.  */
+	case duplicate:
+	  {
+	    register const char *d2, *dend2;
+	    int regno = *p++;   /* Get which register to match against.  */
+	    DEBUG_PRINT2 ("EXECUTING duplicate %d.\n", regno);
+
+	    /* Can't back reference a group which we've never matched.  */
+	    if (REG_UNSET (regstart[regno]) || REG_UNSET (regend[regno]))
+	      goto fail;
+
+	    /* Where in input to try to start matching.  */
+	    d2 = regstart[regno];
+
+	    /* Where to stop matching; if both the place to start and
+	       the place to stop matching are in the same string, then
+	       set to the place to stop, otherwise, for now have to use
+	       the end of the first string.  */
+
+	    dend2 = ((FIRST_STRING_P (regstart[regno])
+		      == FIRST_STRING_P (regend[regno]))
+		     ? regend[regno] : end_match_1);
+	    for (;;)
+	      {
+		/* If necessary, advance to next segment in register
+		   contents.  */
+		while (d2 == dend2)
+		  {
+		    if (dend2 == end_match_2) break;
+		    if (dend2 == regend[regno]) break;
+
+		    /* End of string1 => advance to string2. */
+		    d2 = string2;
+		    dend2 = regend[regno];
+		  }
+		/* At end of register contents => success */
+		if (d2 == dend2) break;
+
+		/* If necessary, advance to next segment in data.  */
+		PREFETCH ();
+
+		/* How many characters left in this segment to match.  */
+		mcnt = dend - d;
+
+		/* Want how many consecutive characters we can match in
+		   one shot, so, if necessary, adjust the count.  */
+		if (mcnt > dend2 - d2)
+		  mcnt = dend2 - d2;
+
+		/* Compare that many; failure if mismatch, else move
+		   past them.  */
+		if (translate
+		    ? bcmp_translate (d, d2, mcnt, translate)
+		    : bcmp (d, d2, mcnt))
+		  goto fail;
+		d += mcnt, d2 += mcnt;
+	      }
+	  }
+	  break;
+
+
+	/* begline matches the empty string at the beginning of the string
+	   (unless `not_bol' is set in `bufp'), and, if
+	   `newline_anchor' is set, after newlines.  */
+	case begline:
+	  DEBUG_PRINT1 ("EXECUTING begline.\n");
+
+	  if (AT_STRINGS_BEG (d))
+	    {
+	      if (!bufp->not_bol) break;
+	    }
+	  else if (d[-1] == '\n' && bufp->newline_anchor)
+	    {
+	      break;
+	    }
+	  /* In all other cases, we fail.  */
+	  goto fail;
+
+
+	/* endline is the dual of begline.  */
+	case endline:
+	  DEBUG_PRINT1 ("EXECUTING endline.\n");
+
+	  if (AT_STRINGS_END (d))
+	    {
+	      if (!bufp->not_eol) break;
+	    }
+
+	  /* We have to ``prefetch'' the next character.  */
+	  else if ((d == end1 ? *string2 : *d) == '\n'
+		   && bufp->newline_anchor)
+	    {
+	      break;
+	    }
+	  goto fail;
+
+
+	/* Match at the very beginning of the data.  */
+	case begbuf:
+	  DEBUG_PRINT1 ("EXECUTING begbuf.\n");
+	  if (AT_STRINGS_BEG (d))
+	    break;
+	  goto fail;
+
+
+	/* Match at the very end of the data.  */
+	case endbuf:
+	  DEBUG_PRINT1 ("EXECUTING endbuf.\n");
+	  if (AT_STRINGS_END (d))
+	    break;
+	  goto fail;
+
+
+	/* on_failure_keep_string_jump is used to optimize `.*\n'.  It
+	   pushes NULL as the value for the string on the stack.  Then
+	   `pop_failure_point' will keep the current value for the
+	   string, instead of restoring it.  To see why, consider
+	   matching `foo\nbar' against `.*\n'.  The .* matches the foo;
+	   then the . fails against the \n.  But the next thing we want
+	   to do is match the \n against the \n; if we restored the
+	   string value, we would be back at the foo.
+
+	   Because this is used only in specific cases, we don't need to
+	   check all the things that `on_failure_jump' does, to make
+	   sure the right things get saved on the stack.  Hence we don't
+	   share its code.  The only reason to push anything on the
+	   stack at all is that otherwise we would have to change
+	   `anychar's code to do something besides goto fail in this
+	   case; that seems worse than this.  */
+	case on_failure_keep_string_jump:
+	  DEBUG_PRINT1 ("EXECUTING on_failure_keep_string_jump");
+
+	  EXTRACT_NUMBER_AND_INCR (mcnt, p);
+	  DEBUG_PRINT3 (" %d (to 0x%x):\n", mcnt, p + mcnt);
+
+	  PUSH_FAILURE_POINT (p + mcnt, NULL, -2);
+	  break;
+
+
+	/* Uses of on_failure_jump:
+
+	   Each alternative starts with an on_failure_jump that points
+	   to the beginning of the next alternative.  Each alternative
+	   except the last ends with a jump that in effect jumps past
+	   the rest of the alternatives.  (They really jump to the
+	   ending jump of the following alternative, because tensioning
+	   these jumps is a hassle.)
+
+	   Repeats start with an on_failure_jump that points past both
+	   the repetition text and either the following jump or
+	   pop_failure_jump back to this on_failure_jump.  */
+	case on_failure_jump:
+	on_failure:
+	  DEBUG_PRINT1 ("EXECUTING on_failure_jump");
+
+	  EXTRACT_NUMBER_AND_INCR (mcnt, p);
+	  DEBUG_PRINT3 (" %d (to 0x%x)", mcnt, p + mcnt);
+
+	  /* If this on_failure_jump comes right before a group (i.e.,
+	     the original * applied to a group), save the information
+	     for that group and all inner ones, so that if we fail back
+	     to this point, the group's information will be correct.
+	     For example, in \(a*\)*\1, we need the preceding group,
+	     and in \(\(a*\)b*\)\2, we need the inner group.  */
+
+	  /* We can't use `p' to check ahead because we push
+	     a failure point to `p + mcnt' after we do this.  */
+	  p1 = p;
+
+	  /* We need to skip no_op's before we look for the
+	     start_memory in case this on_failure_jump is happening as
+	     the result of a completed succeed_n, as in \(a\)\{1,3\}b\1
+	     against aba.  */
+	  while (p1 < pend && (re_opcode_t) *p1 == no_op)
+	    p1++;
+
+	  if (p1 < pend && (re_opcode_t) *p1 == start_memory)
+	    {
+	      /* We have a new highest active register now.  This will
+		 get reset at the start_memory we are about to get to,
+		 but we will have saved all the registers relevant to
+		 this repetition op, as described above.  */
+	      highest_active_reg = *(p1 + 1) + *(p1 + 2);
+	      if (lowest_active_reg == NO_LOWEST_ACTIVE_REG)
+		lowest_active_reg = *(p1 + 1);
+	    }
+
+	  DEBUG_PRINT1 (":\n");
+	  PUSH_FAILURE_POINT (p + mcnt, d, -2);
+	  break;
+
+
+	/* A smart repeat ends with `maybe_pop_jump'.
+	   We change it to either `pop_failure_jump' or `jump'.  */
+	case maybe_pop_jump:
+	  EXTRACT_NUMBER_AND_INCR (mcnt, p);
+	  DEBUG_PRINT2 ("EXECUTING maybe_pop_jump %d.\n", mcnt);
+	  {
+	    register unsigned char *p2 = p;
+
+	    /* Compare the beginning of the repeat with what in the
+	       pattern follows its end. If we can establish that there
+	       is nothing that they would both match, i.e., that we
+	       would have to backtrack because of (as in, e.g., `a*a')
+	       then we can change to pop_failure_jump, because we'll
+	       never have to backtrack.
+
+	       This is not true in the case of alternatives: in
+	       `(a|ab)*' we do need to backtrack to the `ab' alternative
+	       (e.g., if the string was `ab').  But instead of trying to
+	       detect that here, the alternative has put on a dummy
+	       failure point which is what we will end up popping.  */
+
+	    /* Skip over open/close-group commands.  */
+	    while (p2 + 2 < pend
+		   && ((re_opcode_t) *p2 == stop_memory
+		       || (re_opcode_t) *p2 == start_memory))
+	      p2 += 3;			/* Skip over args, too.  */
+
+	    /* If we're at the end of the pattern, we can change.  */
+	    if (p2 == pend)
+	      {
+		/* Consider what happens when matching ":\(.*\)"
+		   against ":/".  I don't really understand this code
+		   yet.  */
+		p[-3] = (unsigned char) pop_failure_jump;
+		DEBUG_PRINT1
+		  ("  End of pattern: change to `pop_failure_jump'.\n");
+	      }
+
+	    else if ((re_opcode_t) *p2 == exactn
+		     || (bufp->newline_anchor && (re_opcode_t) *p2 == endline))
+	      {
+		register unsigned char c
+		  = *p2 == (unsigned char) endline ? '\n' : p2[2];
+		p1 = p + mcnt;
+
+		/* p1[0] ... p1[2] are the `on_failure_jump' corresponding
+		   to the `maybe_finalize_jump' of this case.  Examine what
+		   follows.  */
+		if ((re_opcode_t) p1[3] == exactn && p1[5] != c)
+		  {
+		    p[-3] = (unsigned char) pop_failure_jump;
+		    DEBUG_PRINT3 ("  %c != %c => pop_failure_jump.\n",
+				  c, p1[5]);
+		  }
+
+		else if ((re_opcode_t) p1[3] == charset
+			 || (re_opcode_t) p1[3] == charset_not)
+		  {
+		    int not = (re_opcode_t) p1[3] == charset_not;
+
+		    if (c < (unsigned char) (p1[4] * BYTEWIDTH)
+			&& p1[5 + c / BYTEWIDTH] & (1 << (c % BYTEWIDTH)))
+		      not = !not;
+
+		    /* `not' is equal to 1 if c would match, which means
+			that we can't change to pop_failure_jump.  */
+		    if (!not)
+		      {
+			p[-3] = (unsigned char) pop_failure_jump;
+			DEBUG_PRINT1 ("  No match => pop_failure_jump.\n");
+		      }
+		  }
+	      }
+	  }
+	  p -= 2;		/* Point at relative address again.  */
+	  if ((re_opcode_t) p[-1] != pop_failure_jump)
+	    {
+	      p[-1] = (unsigned char) jump;
+	      DEBUG_PRINT1 ("  Match => jump.\n");
+	      goto unconditional_jump;
+	    }
+	/* Note fall through.  */
+
+
+	/* The end of a simple repeat has a pop_failure_jump back to
+	   its matching on_failure_jump, where the latter will push a
+	   failure point.  The pop_failure_jump takes off failure
+	   points put on by this pop_failure_jump's matching
+	   on_failure_jump; we got through the pattern to here from the
+	   matching on_failure_jump, so didn't fail.  */
+	case pop_failure_jump:
+	  {
+	    /* We need to pass separate storage for the lowest and
+	       highest registers, even though we don't care about the
+	       actual values.  Otherwise, we will restore only one
+	       register from the stack, since lowest will == highest in
+	       `pop_failure_point'.  */
+	    unsigned dummy_low_reg, dummy_high_reg;
+	    unsigned char *pdummy;
+	    const char *sdummy;
+
+	    DEBUG_PRINT1 ("EXECUTING pop_failure_jump.\n");
+	    POP_FAILURE_POINT (sdummy, pdummy,
+			       dummy_low_reg, dummy_high_reg,
+			       reg_dummy, reg_dummy, reg_info_dummy);
+	  }
+	  /* Note fall through.  */
+
+
+	/* Unconditionally jump (without popping any failure points).  */
+	case jump:
+	unconditional_jump:
+	  EXTRACT_NUMBER_AND_INCR (mcnt, p);	/* Get the amount to jump.  */
+	  DEBUG_PRINT2 ("EXECUTING jump %d ", mcnt);
+	  p += mcnt;				/* Do the jump.  */
+	  DEBUG_PRINT2 ("(to 0x%x).\n", p);
+	  break;
+
+
+	/* We need this opcode so we can detect where alternatives end
+	   in `group_match_null_string_p' et al.  */
+	case jump_past_alt:
+	  DEBUG_PRINT1 ("EXECUTING jump_past_alt.\n");
+	  goto unconditional_jump;
+
+
+	/* Normally, the on_failure_jump pushes a failure point, which
+	   then gets popped at pop_failure_jump.  We will end up at
+	   pop_failure_jump, also, and with a pattern of, say, `a+', we
+	   are skipping over the on_failure_jump, so we have to push
+	   something meaningless for pop_failure_jump to pop.  */
+	case dummy_failure_jump:
+	  DEBUG_PRINT1 ("EXECUTING dummy_failure_jump.\n");
+	  /* It doesn't matter what we push for the string here.  What
+	     the code at `fail' tests is the value for the pattern.  */
+	  PUSH_FAILURE_POINT (0, 0, -2);
+	  goto unconditional_jump;
+
+
+	/* At the end of an alternative, we need to push a dummy failure
+	   point in case we are followed by a `pop_failure_jump', because
+	   we don't want the failure point for the alternative to be
+	   popped.  For example, matching `(a|ab)*' against `aab'
+	   requires that we match the `ab' alternative.  */
+	case push_dummy_failure:
+	  DEBUG_PRINT1 ("EXECUTING push_dummy_failure.\n");
+	  /* See comments just above at `dummy_failure_jump' about the
+	     two zeroes.  */
+	  PUSH_FAILURE_POINT (0, 0, -2);
+	  break;
+
+	/* Have to succeed matching what follows at least n times.
+	   After that, handle like `on_failure_jump'.  */
+	case succeed_n:
+	  EXTRACT_NUMBER (mcnt, p + 2);
+	  DEBUG_PRINT2 ("EXECUTING succeed_n %d.\n", mcnt);
+
+	  assert (mcnt >= 0);
+	  /* Originally, this is how many times we HAVE to succeed.  */
+	  if (mcnt > 0)
+	    {
+	       mcnt--;
+	       p += 2;
+	       STORE_NUMBER_AND_INCR (p, mcnt);
+	       DEBUG_PRINT3 ("  Setting 0x%x to %d.\n", p, mcnt);
+	    }
+	  else if (mcnt == 0)
+	    {
+	      DEBUG_PRINT2 ("  Setting two bytes from 0x%x to no_op.\n", p+2);
+	      p[2] = (unsigned char) no_op;
+	      p[3] = (unsigned char) no_op;
+	      goto on_failure;
+	    }
+	  break;
+
+	case jump_n:
+	  EXTRACT_NUMBER (mcnt, p + 2);
+	  DEBUG_PRINT2 ("EXECUTING jump_n %d.\n", mcnt);
+
+	  /* Originally, this is how many times we CAN jump.  */
+	  if (mcnt)
+	    {
+	       mcnt--;
+	       STORE_NUMBER (p + 2, mcnt);
+	       goto unconditional_jump;
+	    }
+	  /* If don't have to jump any more, skip over the rest of command.  */
+	  else
+	    p += 4;
+	  break;
+
+	case set_number_at:
+	  {
+	    DEBUG_PRINT1 ("EXECUTING set_number_at.\n");
+
+	    EXTRACT_NUMBER_AND_INCR (mcnt, p);
+	    p1 = p + mcnt;
+	    EXTRACT_NUMBER_AND_INCR (mcnt, p);
+	    DEBUG_PRINT3 ("  Setting 0x%x to %d.\n", p1, mcnt);
+	    STORE_NUMBER (p1, mcnt);
+	    break;
+	  }
+
+	case wordbound:
+	  DEBUG_PRINT1 ("EXECUTING wordbound.\n");
+	  if (AT_WORD_BOUNDARY (d))
+	    break;
+	  goto fail;
+
+	case notwordbound:
+	  DEBUG_PRINT1 ("EXECUTING notwordbound.\n");
+	  if (AT_WORD_BOUNDARY (d))
+	    goto fail;
+	  break;
+
+	case wordbeg:
+	  DEBUG_PRINT1 ("EXECUTING wordbeg.\n");
+	  if (WORDCHAR_P (d) && (AT_STRINGS_BEG (d) || !WORDCHAR_P (d - 1)))
+	    break;
+	  goto fail;
+
+	case wordend:
+	  DEBUG_PRINT1 ("EXECUTING wordend.\n");
+	  if (!AT_STRINGS_BEG (d) && WORDCHAR_P (d - 1)
+	      && (!WORDCHAR_P (d) || AT_STRINGS_END (d)))
+	    break;
+	  goto fail;
+
+#ifdef emacs
+#ifdef emacs19
+	case before_dot:
+	  DEBUG_PRINT1 ("EXECUTING before_dot.\n");
+	  if (PTR_CHAR_POS ((unsigned char *) d) >= point)
+	    goto fail;
+	  break;
+
+	case at_dot:
+	  DEBUG_PRINT1 ("EXECUTING at_dot.\n");
+	  if (PTR_CHAR_POS ((unsigned char *) d) != point)
+	    goto fail;
+	  break;
+
+	case after_dot:
+	  DEBUG_PRINT1 ("EXECUTING after_dot.\n");
+	  if (PTR_CHAR_POS ((unsigned char *) d) <= point)
+	    goto fail;
+	  break;
+#else /* not emacs19 */
+	case at_dot:
+	  DEBUG_PRINT1 ("EXECUTING at_dot.\n");
+	  if (PTR_CHAR_POS ((unsigned char *) d) + 1 != point)
+	    goto fail;
+	  break;
+#endif /* not emacs19 */
+
+	case syntaxspec:
+	  DEBUG_PRINT2 ("EXECUTING syntaxspec %d.\n", mcnt);
+	  mcnt = *p++;
+	  goto matchsyntax;
+
+	case wordchar:
+	  DEBUG_PRINT1 ("EXECUTING Emacs wordchar.\n");
+	  mcnt = (int) Sword;
+	matchsyntax:
+	  PREFETCH ();
+	  if (SYNTAX (*d++) != (enum syntaxcode) mcnt)
+	    goto fail;
+	  SET_REGS_MATCHED ();
+	  break;
+
+	case notsyntaxspec:
+	  DEBUG_PRINT2 ("EXECUTING notsyntaxspec %d.\n", mcnt);
+	  mcnt = *p++;
+	  goto matchnotsyntax;
+
+	case notwordchar:
+	  DEBUG_PRINT1 ("EXECUTING Emacs notwordchar.\n");
+	  mcnt = (int) Sword;
+	matchnotsyntax:
+	  PREFETCH ();
+	  if (SYNTAX (*d++) == (enum syntaxcode) mcnt)
+	    goto fail;
+	  SET_REGS_MATCHED ();
+	  break;
+
+#else /* not emacs */
+	case wordchar:
+	  DEBUG_PRINT1 ("EXECUTING non-Emacs wordchar.\n");
+	  PREFETCH ();
+	  if (!WORDCHAR_P (d))
+	    goto fail;
+	  SET_REGS_MATCHED ();
+	  d++;
+	  break;
+
+	case notwordchar:
+	  DEBUG_PRINT1 ("EXECUTING non-Emacs notwordchar.\n");
+	  PREFETCH ();
+	  if (WORDCHAR_P (d))
+	    goto fail;
+	  SET_REGS_MATCHED ();
+	  d++;
+	  break;
+#endif /* not emacs */
+
+	default:
+	  abort ();
+	}
+      continue;  /* Successfully executed one pattern command; keep going.  */
+
+
+    /* We goto here if a matching operation fails. */
+    fail:
+      if (!FAIL_STACK_EMPTY ())
+	{ /* A restart point is known.  Restore to that state.  */
+	  DEBUG_PRINT1 ("\nFAIL:\n");
+	  POP_FAILURE_POINT (d, p,
+			     lowest_active_reg, highest_active_reg,
+			     regstart, regend, reg_info);
+
+	  /* If this failure point is a dummy, try the next one.  */
+	  if (!p)
+	    goto fail;
+
+	  /* If we failed to the end of the pattern, don't examine *p.  */
+	  assert (p <= pend);
+	  if (p < pend)
+	    {
+	      boolean is_a_jump_n = false;
+
+	      /* If failed to a backwards jump that's part of a repetition
+		 loop, need to pop this failure point and use the next one.  */
+	      switch ((re_opcode_t) *p)
+		{
+		case jump_n:
+		  is_a_jump_n = true;
+		case maybe_pop_jump:
+		case pop_failure_jump:
+		case jump:
+		  p1 = p + 1;
+		  EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+		  p1 += mcnt;
+
+		  if ((is_a_jump_n && (re_opcode_t) *p1 == succeed_n)
+		      || (!is_a_jump_n
+			  && (re_opcode_t) *p1 == on_failure_jump))
+		    goto fail;
+		  break;
+		default:
+		  /* do nothing */ ;
+		}
+	    }
+
+	  if (d >= string1 && d <= end1)
+	    dend = end_match_1;
+	}
+      else
+	break;   /* Matching at this starting point really fails.  */
+    } /* for (;;) */
+
+  if (best_regs_set)
+    goto restore_best_regs;
+
+  FREE_VARIABLES ();
+
+  return -1;         			/* Failure to match.  */
+} /* re_match_2 */
+
+/* Subroutine definitions for re_match_2.  */
+
+
+/* We are passed P pointing to a register number after a start_memory.
+
+   Return true if the pattern up to the corresponding stop_memory can
+   match the empty string, and false otherwise.
+
+   If we find the matching stop_memory, sets P to point to one past its number.
+   Otherwise, sets P to an undefined byte less than or equal to END.
+
+   We don't handle duplicates properly (yet).  */
+
+static boolean
+group_match_null_string_p (p, end, reg_info)
+    unsigned char **p, *end;
+    register_info_type *reg_info;
+{
+  int mcnt;
+  /* Point to after the args to the start_memory.  */
+  unsigned char *p1 = *p + 2;
+
+  while (p1 < end)
+    {
+      /* Skip over opcodes that can match nothing, and return true or
+	 false, as appropriate, when we get to one that can't, or to the
+	 matching stop_memory.  */
+
+      switch ((re_opcode_t) *p1)
+	{
+	/* Could be either a loop or a series of alternatives.  */
+	case on_failure_jump:
+	  p1++;
+	  EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+
+	  /* If the next operation is not a jump backwards in the
+	     pattern.  */
+
+	  if (mcnt >= 0)
+	    {
+	      /* Go through the on_failure_jumps of the alternatives,
+		 seeing if any of the alternatives cannot match nothing.
+		 The last alternative starts with only a jump,
+		 whereas the rest start with on_failure_jump and end
+		 with a jump, e.g., here is the pattern for `a|b|c':
+
+		 /on_failure_jump/0/6/exactn/1/a/jump_past_alt/0/6
+		 /on_failure_jump/0/6/exactn/1/b/jump_past_alt/0/3
+		 /exactn/1/c
+
+		 So, we have to first go through the first (n-1)
+		 alternatives and then deal with the last one separately.  */
+
+
+	      /* Deal with the first (n-1) alternatives, which start
+		 with an on_failure_jump (see above) that jumps to right
+		 past a jump_past_alt.  */
+
+	      while ((re_opcode_t) p1[mcnt-3] == jump_past_alt)
+		{
+		  /* `mcnt' holds how many bytes long the alternative
+		     is, including the ending `jump_past_alt' and
+		     its number.  */
+
+		  if (!alt_match_null_string_p (p1, p1 + mcnt - 3,
+						      reg_info))
+		    return false;
+
+		  /* Move to right after this alternative, including the
+		     jump_past_alt.  */
+		  p1 += mcnt;
+
+		  /* Break if it's the beginning of an n-th alternative
+		     that doesn't begin with an on_failure_jump.  */
+		  if ((re_opcode_t) *p1 != on_failure_jump)
+		    break;
+
+		  /* Still have to check that it's not an n-th
+		     alternative that starts with an on_failure_jump.  */
+		  p1++;
+		  EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+		  if ((re_opcode_t) p1[mcnt-3] != jump_past_alt)
+		    {
+		      /* Get to the beginning of the n-th alternative.  */
+		      p1 -= 3;
+		      break;
+		    }
+		}
+
+	      /* Deal with the last alternative: go back and get number
+		 of the `jump_past_alt' just before it.  `mcnt' contains
+		 the length of the alternative.  */
+	      EXTRACT_NUMBER (mcnt, p1 - 2);
+
+	      if (!alt_match_null_string_p (p1, p1 + mcnt, reg_info))
+		return false;
+
+	      p1 += mcnt;	/* Get past the n-th alternative.  */
+	    } /* if mcnt > 0 */
+	  break;
+
+
+	case stop_memory:
+	  assert (p1[1] == **p);
+	  *p = p1 + 2;
+	  return true;
+
+
+	default:
+	  if (!common_op_match_null_string_p (&p1, end, reg_info))
+	    return false;
+	}
+    } /* while p1 < end */
+
+  return false;
+} /* group_match_null_string_p */
+
+
+/* Similar to group_match_null_string_p, but doesn't deal with alternatives:
+   It expects P to be the first byte of a single alternative and END one
+   byte past the last. The alternative can contain groups.  */
+
+static boolean
+alt_match_null_string_p (p, end, reg_info)
+    unsigned char *p, *end;
+    register_info_type *reg_info;
+{
+  int mcnt;
+  unsigned char *p1 = p;
+
+  while (p1 < end)
+    {
+      /* Skip over opcodes that can match nothing, and break when we get
+	 to one that can't.  */
+
+      switch ((re_opcode_t) *p1)
+	{
+	/* It's a loop.  */
+	case on_failure_jump:
+	  p1++;
+	  EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+	  p1 += mcnt;
+	  break;
+
+	default:
+	  if (!common_op_match_null_string_p (&p1, end, reg_info))
+	    return false;
+	}
+    }  /* while p1 < end */
+
+  return true;
+} /* alt_match_null_string_p */
+
+
+/* Deals with the ops common to group_match_null_string_p and
+   alt_match_null_string_p.
+
+   Sets P to one after the op and its arguments, if any.  */
+
+static boolean
+common_op_match_null_string_p (p, end, reg_info)
+    unsigned char **p, *end;
+    register_info_type *reg_info;
+{
+  int mcnt;
+  boolean ret;
+  int reg_no;
+  unsigned char *p1 = *p;
+
+  switch ((re_opcode_t) *p1++)
+    {
+    case no_op:
+    case begline:
+    case endline:
+    case begbuf:
+    case endbuf:
+    case wordbeg:
+    case wordend:
+    case wordbound:
+    case notwordbound:
+#ifdef emacs
+    case before_dot:
+    case at_dot:
+    case after_dot:
+#endif
+      break;
+
+    case start_memory:
+      reg_no = *p1;
+      assert (reg_no > 0 && reg_no <= MAX_REGNUM);
+      ret = group_match_null_string_p (&p1, end, reg_info);
+
+      /* Have to set this here in case we're checking a group which
+	 contains a group and a back reference to it.  */
+
+      if (REG_MATCH_NULL_STRING_P (reg_info[reg_no]) == MATCH_NULL_UNSET_VALUE)
+	REG_MATCH_NULL_STRING_P (reg_info[reg_no]) = ret;
+
+      if (!ret)
+	return false;
+      break;
+
+    /* If this is an optimized succeed_n for zero times, make the jump.  */
+    case jump:
+      EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+      if (mcnt >= 0)
+	p1 += mcnt;
+      else
+	return false;
+      break;
+
+    case succeed_n:
+      /* Get to the number of times to succeed.  */
+      p1 += 2;
+      EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+
+      if (mcnt == 0)
+	{
+	  p1 -= 4;
+	  EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+	  p1 += mcnt;
+	}
+      else
+	return false;
+      break;
+
+    case duplicate:
+      if (!REG_MATCH_NULL_STRING_P (reg_info[*p1]))
+	return false;
+      break;
+
+    case set_number_at:
+      p1 += 4;
+
+    default:
+      /* All other opcodes mean we cannot match the empty string.  */
+      return false;
+  }
+
+  *p = p1;
+  return true;
+} /* common_op_match_null_string_p */
+
+
+/* Return zero if TRANSLATE[S1] and TRANSLATE[S2] are identical for LEN
+   bytes; nonzero otherwise.  */
+
+static int
+bcmp_translate(
+     unsigned char *s1,
+     unsigned char *s2,
+     int len,
+     char *translate
+)
+{
+  register unsigned char *p1 = s1, *p2 = s2;
+  while (len)
+    {
+      if (translate[*p1++] != translate[*p2++]) return 1;
+      len--;
+    }
+  return 0;
+}
+
+/* Entry points for GNU code.  */
+
+/* re_compile_pattern is the GNU regular expression compiler: it
+   compiles PATTERN (of length SIZE) and puts the result in BUFP.
+   Returns 0 if the pattern was valid, otherwise an error string.
+
+   Assumes the `allocated' (and perhaps `buffer') and `translate' fields
+   are set in BUFP on entry.
+
+   We call regex_compile to do the actual compilation.  */
+
+const char *
+re_compile_pattern (pattern, length, bufp)
+     const char *pattern;
+     int length;
+     struct re_pattern_buffer *bufp;
+{
+  reg_errcode_t ret;
+
+  /* GNU code is written to assume at least RE_NREGS registers will be set
+     (and at least one extra will be -1).  */
+  bufp->regs_allocated = REGS_UNALLOCATED;
+
+  /* And GNU code determines whether or not to get register information
+     by passing null for the REGS argument to re_match, etc., not by
+     setting no_sub.  */
+  bufp->no_sub = 0;
+
+  /* Match anchors at newline.  */
+  bufp->newline_anchor = 1;
+
+  ret = regex_compile (pattern, length, re_syntax_options, bufp);
+
+  return re_error_msg[(int) ret];
+}
+
+/* Entry points compatible with 4.2 BSD regex library.  We don't define
+   them if this is an Emacs or POSIX compilation.  */
+
+#if !defined (emacs) && !defined (_POSIX_SOURCE)
+
+/* BSD has one and only one pattern buffer.  */
+static struct re_pattern_buffer re_comp_buf;
+
+char *
+re_comp (s)
+    const char *s;
+{
+  reg_errcode_t ret;
+
+  if (!s)
+    {
+      if (!re_comp_buf.buffer)
+	return "No previous regular expression";
+      return 0;
+    }
+
+  if (!re_comp_buf.buffer)
+    {
+      re_comp_buf.buffer = (unsigned char *) malloc (200);
+      if (re_comp_buf.buffer == NULL)
+	return "Memory exhausted";
+      re_comp_buf.allocated = 200;
+
+      re_comp_buf.fastmap = (char *) malloc (1 << BYTEWIDTH);
+      if (re_comp_buf.fastmap == NULL)
+	return "Memory exhausted";
+    }
+
+  /* Since `re_exec' always passes NULL for the `regs' argument, we
+     don't need to initialize the pattern buffer fields which affect it.  */
+
+  /* Match anchors at newlines.  */
+  re_comp_buf.newline_anchor = 1;
+
+  ret = regex_compile (s, strlen (s), re_syntax_options, &re_comp_buf);
+
+  /* Yes, we're discarding `const' here.  */
+  return (char *) re_error_msg[(int) ret];
+}
+
+
+int
+re_exec (s)
+    const char *s;
+{
+  const int len = strlen (s);
+  return
+    0 <= re_search (&re_comp_buf, s, len, 0, len, (struct re_registers *) 0);
+}
+#endif /* not emacs and not _POSIX_SOURCE */
+
+/* POSIX.2 functions.  Don't define these for Emacs.  */
+
+#ifndef emacs
+
+/* regcomp takes a regular expression as a string and compiles it.
+
+   PREG is a regex_t *.  We do not expect any fields to be initialized,
+   since POSIX says we shouldn't.  Thus, we set
+
+     `buffer' to the compiled pattern;
+     `used' to the length of the compiled pattern;
+     `syntax' to RE_SYNTAX_POSIX_EXTENDED if the
+       REG_EXTENDED bit in CFLAGS is set; otherwise, to
+       RE_SYNTAX_POSIX_BASIC;
+     `newline_anchor' to REG_NEWLINE being set in CFLAGS;
+     `fastmap' and `fastmap_accurate' to zero;
+     `re_nsub' to the number of subexpressions in PATTERN.
+
+   PATTERN is the address of the pattern string.
+
+   CFLAGS is a series of bits which affect compilation.
+
+     If REG_EXTENDED is set, we use POSIX extended syntax; otherwise, we
+     use POSIX basic syntax.
+
+     If REG_NEWLINE is set, then . and [^...] don't match newline.
+     Also, regexec will try a match beginning after every newline.
+
+     If REG_ICASE is set, then we considers upper- and lowercase
+     versions of letters to be equivalent when matching.
+
+     If REG_NOSUB is set, then when PREG is passed to regexec, that
+     routine will report only success or failure, and nothing about the
+     registers.
+
+   It returns 0 if it succeeds, nonzero if it doesn't.  (See regex.h for
+   the return codes and their meanings.)  */
+
+int
+regcomp (preg, pattern, cflags)
+    regex_t *preg;
+    const char *pattern;
+    int cflags;
+{
+  reg_errcode_t ret;
+  unsigned syntax
+    = (cflags & REG_EXTENDED) ?
+      RE_SYNTAX_POSIX_EXTENDED : RE_SYNTAX_POSIX_BASIC;
+
+  /* regex_compile will allocate the space for the compiled pattern.  */
+  preg->buffer = 0;
+  preg->allocated = 0;
+
+  /* Don't bother to use a fastmap when searching.  This simplifies the
+     REG_NEWLINE case: if we used a fastmap, we'd have to put all the
+     characters after newlines into the fastmap.  This way, we just try
+     every character.  */
+  preg->fastmap = 0;
+
+  if (cflags & REG_ICASE)
+    {
+      unsigned i;
+
+      preg->translate = (char *) malloc (CHAR_SET_SIZE);
+      if (preg->translate == NULL)
+	return (int) REG_ESPACE;
+
+      /* Map uppercase characters to corresponding lowercase ones.  */
+      for (i = 0; i < CHAR_SET_SIZE; i++)
+	preg->translate[i] = ISUPPER (i) ? tolower (i) : i;
+    }
+  else
+    preg->translate = NULL;
+
+  /* If REG_NEWLINE is set, newlines are treated differently.  */
+  if (cflags & REG_NEWLINE)
+    { /* REG_NEWLINE implies neither . nor [^...] match newline.  */
+      syntax &= ~RE_DOT_NEWLINE;
+      syntax |= RE_HAT_LISTS_NOT_NEWLINE;
+      /* It also changes the matching behavior.  */
+      preg->newline_anchor = 1;
+    }
+  else
+    preg->newline_anchor = 0;
+
+  preg->no_sub = !!(cflags & REG_NOSUB);
+
+  /* POSIX says a null character in the pattern terminates it, so we
+     can use strlen here in compiling the pattern.  */
+  ret = regex_compile (pattern, strlen (pattern), syntax, preg);
+
+  /* POSIX doesn't distinguish between an unmatched open-group and an
+     unmatched close-group: both are REG_EPAREN.  */
+  if (ret == REG_ERPAREN) ret = REG_EPAREN;
+
+  return (int) ret;
+}
+
+
+/* regexec searches for a given pattern, specified by PREG, in the
+   string STRING.
+
+   If NMATCH is zero or REG_NOSUB was set in the cflags argument to
+   `regcomp', we ignore PMATCH.  Otherwise, we assume PMATCH has at
+   least NMATCH elements, and we set them to the offsets of the
+   corresponding matched substrings.
+
+   EFLAGS specifies `execution flags' which affect matching: if
+   REG_NOTBOL is set, then ^ does not match at the beginning of the
+   string; if REG_NOTEOL is set, then $ does not match at the end.
+
+   We return 0 if we find a match and REG_NOMATCH if not.  */
+
+int
+regexec (preg, string, nmatch, pmatch, eflags)
+    const regex_t *preg;
+    const char *string;
+    size_t nmatch;
+    regmatch_t pmatch[];
+    int eflags;
+{
+  int ret;
+  struct re_registers regs;
+  regex_t private_preg;
+  int len = strlen (string);
+  boolean want_reg_info = !preg->no_sub && nmatch > 0;
+
+  private_preg = *preg;
+
+  private_preg.not_bol = !!(eflags & REG_NOTBOL);
+  private_preg.not_eol = !!(eflags & REG_NOTEOL);
+
+  /* The user has told us exactly how many registers to return
+     information about, via `nmatch'.  We have to pass that on to the
+     matching routines.  */
+  private_preg.regs_allocated = REGS_FIXED;
+
+  if (want_reg_info)
+    {
+      regs.num_regs = nmatch;
+      regs.start = TALLOC (nmatch, regoff_t);
+      regs.end = TALLOC (nmatch, regoff_t);
+      if (regs.start == NULL || regs.end == NULL)
+	return (int) REG_NOMATCH;
+    }
+
+  /* Perform the searching operation.  */
+  ret = re_search (&private_preg, string, len,
+		   /* start: */ 0, /* range: */ len,
+		   want_reg_info ? &regs : (struct re_registers *) 0);
+
+  /* Copy the register information to the POSIX structure.  */
+  if (want_reg_info)
+    {
+      if (ret >= 0)
+	{
+	  unsigned r;
+
+	  for (r = 0; r < nmatch; r++)
+	    {
+	      pmatch[r].rm_so = regs.start[r];
+	      pmatch[r].rm_eo = regs.end[r];
+	    }
+	}
+
+      /* If we needed the temporary register info, free the space now.  */
+      free (regs.start);
+      free (regs.end);
+    }
+
+  /* We want zero return to mean success, unlike `re_search'.  */
+  return ret >= 0 ? (int) REG_NOERROR : (int) REG_NOMATCH;
+}
+
+
+/* Returns a message corresponding to an error code, ERRCODE, returned
+   from either regcomp or regexec.   We don't use PREG here.  */
+
+size_t
+regerror (errcode, preg, errbuf, errbuf_size)
+    int errcode;
+    const regex_t *preg;
+    char *errbuf;
+    size_t errbuf_size;
+{
+  const char *msg;
+  size_t msg_size;
+
+  if (errcode < 0
+      || errcode >= (sizeof (re_error_msg) / sizeof (re_error_msg[0])))
+    /* Only error codes returned by the rest of the code should be passed
+       to this routine.  If we are given anything else, or if other regex
+       code generates an invalid error code, then the program has a bug.
+       Dump core so we can fix it.  */
+    abort ();
+
+  msg = re_error_msg[errcode];
+
+  /* POSIX doesn't require that we do anything in this case, but why
+     not be nice.  */
+  if (! msg)
+    msg = "Success";
+
+  msg_size = strlen (msg) + 1; /* Includes the null.  */
+
+  if (errbuf_size != 0)
+    {
+      if (msg_size > errbuf_size)
+	{
+	  strncpy (errbuf, msg, errbuf_size - 1);
+	  errbuf[errbuf_size - 1] = 0;
+	}
+      else
+	strcpy (errbuf, msg);
+    }
+
+  return msg_size;
+}
+
+
+/* Free dynamically allocated space used by PREG.  */
+
+void
+regfree (preg)
+    regex_t *preg;
+{
+  if (preg->buffer != NULL)
+    free (preg->buffer);
+  preg->buffer = NULL;
+
+  preg->allocated = 0;
+  preg->used = 0;
+
+  if (preg->fastmap != NULL)
+    free (preg->fastmap);
+  preg->fastmap = NULL;
+  preg->fastmap_accurate = 0;
+
+  if (preg->translate != NULL)
+    free (preg->translate);
+  preg->translate = NULL;
+}
+
+#endif /* not emacs  */
+
+/*
+Local variables:
+make-backup-files: t
+version-control: t
+trim-versions-without-asking: nil
+End:
+*/
diff --git a/compat/regex.h b/compat/regex.h
new file mode 100644
index 000000000..6eb64f140
--- /dev/null
+++ b/compat/regex.h
@@ -0,0 +1,490 @@
+/* Definitions for data structures and routines for the regular
+   expression library, version 0.12.
+
+   Copyright (C) 1985, 1989, 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#ifndef __REGEXP_LIBRARY_H__
+#define __REGEXP_LIBRARY_H__
+
+/* POSIX says that <sys/types.h> must be included (by the caller) before
+   <regex.h>.  */
+
+#ifdef VMS
+/* VMS doesn't have `size_t' in <sys/types.h>, even though POSIX says it
+   should be there.  */
+#include <stddef.h>
+#endif
+
+
+/* The following bits are used to determine the regexp syntax we
+   recognize.  The set/not-set meanings are chosen so that Emacs syntax
+   remains the value 0.  The bits are given in alphabetical order, and
+   the definitions shifted by one from the previous bit; thus, when we
+   add or remove a bit, only one other definition need change.  */
+typedef unsigned reg_syntax_t;
+
+/* If this bit is not set, then \ inside a bracket expression is literal.
+   If set, then such a \ quotes the following character.  */
+#define RE_BACKSLASH_ESCAPE_IN_LISTS (1)
+
+/* If this bit is not set, then + and ? are operators, and \+ and \? are
+     literals.
+   If set, then \+ and \? are operators and + and ? are literals.  */
+#define RE_BK_PLUS_QM (RE_BACKSLASH_ESCAPE_IN_LISTS << 1)
+
+/* If this bit is set, then character classes are supported.  They are:
+     [:alpha:], [:upper:], [:lower:],  [:digit:], [:alnum:], [:xdigit:],
+     [:space:], [:print:], [:punct:], [:graph:], and [:cntrl:].
+   If not set, then character classes are not supported.  */
+#define RE_CHAR_CLASSES (RE_BK_PLUS_QM << 1)
+
+/* If this bit is set, then ^ and $ are always anchors (outside bracket
+     expressions, of course).
+   If this bit is not set, then it depends:
+	^  is an anchor if it is at the beginning of a regular
+	   expression or after an open-group or an alternation operator;
+	$  is an anchor if it is at the end of a regular expression, or
+	   before a close-group or an alternation operator.
+
+   This bit could be (re)combined with RE_CONTEXT_INDEP_OPS, because
+   POSIX draft 11.2 says that * etc. in leading positions is undefined.
+   We already implemented a previous draft which made those constructs
+   invalid, though, so we haven't changed the code back.  */
+#define RE_CONTEXT_INDEP_ANCHORS (RE_CHAR_CLASSES << 1)
+
+/* If this bit is set, then special characters are always special
+     regardless of where they are in the pattern.
+   If this bit is not set, then special characters are special only in
+     some contexts; otherwise they are ordinary.  Specifically,
+     * + ? and intervals are only special when not after the beginning,
+     open-group, or alternation operator.  */
+#define RE_CONTEXT_INDEP_OPS (RE_CONTEXT_INDEP_ANCHORS << 1)
+
+/* If this bit is set, then *, +, ?, and { cannot be first in an re or
+     immediately after an alternation or begin-group operator.  */
+#define RE_CONTEXT_INVALID_OPS (RE_CONTEXT_INDEP_OPS << 1)
+
+/* If this bit is set, then . matches newline.
+   If not set, then it doesn't.  */
+#define RE_DOT_NEWLINE (RE_CONTEXT_INVALID_OPS << 1)
+
+/* If this bit is set, then . doesn't match NUL.
+   If not set, then it does.  */
+#define RE_DOT_NOT_NULL (RE_DOT_NEWLINE << 1)
+
+/* If this bit is set, nonmatching lists [^...] do not match newline.
+   If not set, they do.  */
+#define RE_HAT_LISTS_NOT_NEWLINE (RE_DOT_NOT_NULL << 1)
+
+/* If this bit is set, either \{...\} or {...} defines an
+     interval, depending on RE_NO_BK_BRACES.
+   If not set, \{, \}, {, and } are literals.  */
+#define RE_INTERVALS (RE_HAT_LISTS_NOT_NEWLINE << 1)
+
+/* If this bit is set, +, ? and | aren't recognized as operators.
+   If not set, they are.  */
+#define RE_LIMITED_OPS (RE_INTERVALS << 1)
+
+/* If this bit is set, newline is an alternation operator.
+   If not set, newline is literal.  */
+#define RE_NEWLINE_ALT (RE_LIMITED_OPS << 1)
+
+/* If this bit is set, then `{...}' defines an interval, and \{ and \}
+     are literals.
+  If not set, then `\{...\}' defines an interval.  */
+#define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)
+
+/* If this bit is set, (...) defines a group, and \( and \) are literals.
+   If not set, \(...\) defines a group, and ( and ) are literals.  */
+#define RE_NO_BK_PARENS (RE_NO_BK_BRACES << 1)
+
+/* If this bit is set, then \<digit> matches <digit>.
+   If not set, then \<digit> is a back-reference.  */
+#define RE_NO_BK_REFS (RE_NO_BK_PARENS << 1)
+
+/* If this bit is set, then | is an alternation operator, and \| is literal.
+   If not set, then \| is an alternation operator, and | is literal.  */
+#define RE_NO_BK_VBAR (RE_NO_BK_REFS << 1)
+
+/* If this bit is set, then an ending range point collating higher
+     than the starting range point, as in [z-a], is invalid.
+   If not set, then when ending range point collates higher than the
+     starting range point, the range is ignored.  */
+#define RE_NO_EMPTY_RANGES (RE_NO_BK_VBAR << 1)
+
+/* If this bit is set, then an unmatched ) is ordinary.
+   If not set, then an unmatched ) is invalid.  */
+#define RE_UNMATCHED_RIGHT_PAREN_ORD (RE_NO_EMPTY_RANGES << 1)
+
+/* This global variable defines the particular regexp syntax to use (for
+   some interfaces).  When a regexp is compiled, the syntax used is
+   stored in the pattern buffer, so changing this does not affect
+   already-compiled regexps.  */
+extern reg_syntax_t re_syntax_options;
+
+/* Define combinations of the above bits for the standard possibilities.
+   (The [[[ comments delimit what gets put into the Texinfo file, so
+   don't delete them!)  */
+/* [[[begin syntaxes]]] */
+#define RE_SYNTAX_EMACS 0
+
+#define RE_SYNTAX_AWK							\
+  (RE_BACKSLASH_ESCAPE_IN_LISTS | RE_DOT_NOT_NULL			\
+   | RE_NO_BK_PARENS            | RE_NO_BK_REFS				\
+   | RE_NO_BK_VBAR               | RE_NO_EMPTY_RANGES			\
+   | RE_UNMATCHED_RIGHT_PAREN_ORD)
+
+#define RE_SYNTAX_POSIX_AWK 						\
+  (RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS)
+
+#define RE_SYNTAX_GREP							\
+  (RE_BK_PLUS_QM              | RE_CHAR_CLASSES				\
+   | RE_HAT_LISTS_NOT_NEWLINE | RE_INTERVALS				\
+   | RE_NEWLINE_ALT)
+
+#define RE_SYNTAX_EGREP							\
+  (RE_CHAR_CLASSES        | RE_CONTEXT_INDEP_ANCHORS			\
+   | RE_CONTEXT_INDEP_OPS | RE_HAT_LISTS_NOT_NEWLINE			\
+   | RE_NEWLINE_ALT       | RE_NO_BK_PARENS				\
+   | RE_NO_BK_VBAR)
+
+#define RE_SYNTAX_POSIX_EGREP						\
+  (RE_SYNTAX_EGREP | RE_INTERVALS | RE_NO_BK_BRACES)
+
+/* P1003.2/D11.2, section 4.20.7.1, lines 5078ff.  */
+#define RE_SYNTAX_ED RE_SYNTAX_POSIX_BASIC
+
+#define RE_SYNTAX_SED RE_SYNTAX_POSIX_BASIC
+
+/* Syntax bits common to both basic and extended POSIX regex syntax.  */
+#define _RE_SYNTAX_POSIX_COMMON						\
+  (RE_CHAR_CLASSES | RE_DOT_NEWLINE      | RE_DOT_NOT_NULL		\
+   | RE_INTERVALS  | RE_NO_EMPTY_RANGES)
+
+#define RE_SYNTAX_POSIX_BASIC						\
+  (_RE_SYNTAX_POSIX_COMMON | RE_BK_PLUS_QM)
+
+/* Differs from ..._POSIX_BASIC only in that RE_BK_PLUS_QM becomes
+   RE_LIMITED_OPS, i.e., \? \+ \| are not recognized.  Actually, this
+   isn't minimal, since other operators, such as \`, aren't disabled.  */
+#define RE_SYNTAX_POSIX_MINIMAL_BASIC					\
+  (_RE_SYNTAX_POSIX_COMMON | RE_LIMITED_OPS)
+
+#define RE_SYNTAX_POSIX_EXTENDED					\
+  (_RE_SYNTAX_POSIX_COMMON | RE_CONTEXT_INDEP_ANCHORS			\
+   | RE_CONTEXT_INDEP_OPS  | RE_NO_BK_BRACES				\
+   | RE_NO_BK_PARENS       | RE_NO_BK_VBAR				\
+   | RE_UNMATCHED_RIGHT_PAREN_ORD)
+
+/* Differs from ..._POSIX_EXTENDED in that RE_CONTEXT_INVALID_OPS
+   replaces RE_CONTEXT_INDEP_OPS and RE_NO_BK_REFS is added.  */
+#define RE_SYNTAX_POSIX_MINIMAL_EXTENDED				\
+  (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS			\
+   | RE_CONTEXT_INVALID_OPS | RE_NO_BK_BRACES				\
+   | RE_NO_BK_PARENS        | RE_NO_BK_REFS				\
+   | RE_NO_BK_VBAR	    | RE_UNMATCHED_RIGHT_PAREN_ORD)
+/* [[[end syntaxes]]] */
+
+/* Maximum number of duplicates an interval can allow.  Some systems
+   (erroneously) define this in other header files, but we want our
+   value, so remove any previous define.  */
+#ifdef RE_DUP_MAX
+#undef RE_DUP_MAX
+#endif
+#define RE_DUP_MAX ((1 << 15) - 1)
+
+
+/* POSIX `cflags' bits (i.e., information for `regcomp').  */
+
+/* If this bit is set, then use extended regular expression syntax.
+   If not set, then use basic regular expression syntax.  */
+#define REG_EXTENDED 1
+
+/* If this bit is set, then ignore case when matching.
+   If not set, then case is significant.  */
+#define REG_ICASE (REG_EXTENDED << 1)
+
+/* If this bit is set, then anchors do not match at newline
+     characters in the string.
+   If not set, then anchors do match at newlines.  */
+#define REG_NEWLINE (REG_ICASE << 1)
+
+/* If this bit is set, then report only success or fail in regexec.
+   If not set, then returns differ between not matching and errors.  */
+#define REG_NOSUB (REG_NEWLINE << 1)
+
+
+/* POSIX `eflags' bits (i.e., information for regexec).  */
+
+/* If this bit is set, then the beginning-of-line operator doesn't match
+     the beginning of the string (presumably because it's not the
+     beginning of a line).
+   If not set, then the beginning-of-line operator does match the
+     beginning of the string.  */
+#define REG_NOTBOL 1
+
+/* Like REG_NOTBOL, except for the end-of-line.  */
+#define REG_NOTEOL (1 << 1)
+
+
+/* If any error codes are removed, changed, or added, update the
+   `re_error_msg' table in regex.c.  */
+typedef enum
+{
+  REG_NOERROR = 0,	/* Success.  */
+  REG_NOMATCH,		/* Didn't find a match (for regexec).  */
+
+  /* POSIX regcomp return error codes.  (In the order listed in the
+     standard.)  */
+  REG_BADPAT,		/* Invalid pattern.  */
+  REG_ECOLLATE,		/* Not implemented.  */
+  REG_ECTYPE,		/* Invalid character class name.  */
+  REG_EESCAPE,		/* Trailing backslash.  */
+  REG_ESUBREG,		/* Invalid back reference.  */
+  REG_EBRACK,		/* Unmatched left bracket.  */
+  REG_EPAREN,		/* Parenthesis imbalance.  */
+  REG_EBRACE,		/* Unmatched \{.  */
+  REG_BADBR,		/* Invalid contents of \{\}.  */
+  REG_ERANGE,		/* Invalid range end.  */
+  REG_ESPACE,		/* Ran out of memory.  */
+  REG_BADRPT,		/* No preceding re for repetition op.  */
+
+  /* Error codes we've added.  */
+  REG_EEND,		/* Premature end.  */
+  REG_ESIZE,		/* Compiled pattern bigger than 2^16 bytes.  */
+  REG_ERPAREN		/* Unmatched ) or \); not returned from regcomp.  */
+} reg_errcode_t;
+
+/* This data structure represents a compiled pattern.  Before calling
+   the pattern compiler, the fields `buffer', `allocated', `fastmap',
+   `translate', and `no_sub' can be set.  After the pattern has been
+   compiled, the `re_nsub' field is available.  All other fields are
+   private to the regex routines.  */
+
+struct re_pattern_buffer
+{
+/* [[[begin pattern_buffer]]] */
+	/* Space that holds the compiled pattern.  It is declared as
+	  `unsigned char *' because its elements are
+	   sometimes used as array indexes.  */
+  unsigned char *buffer;
+
+	/* Number of bytes to which `buffer' points.  */
+  unsigned long allocated;
+
+	/* Number of bytes actually used in `buffer'.  */
+  unsigned long used;
+
+	/* Syntax setting with which the pattern was compiled.  */
+  reg_syntax_t syntax;
+
+	/* Pointer to a fastmap, if any, otherwise zero.  re_search uses
+	   the fastmap, if there is one, to skip over impossible
+	   starting points for matches.  */
+  char *fastmap;
+
+	/* Either a translate table to apply to all characters before
+	   comparing them, or zero for no translation.  The translation
+	   is applied to a pattern when it is compiled and to a string
+	   when it is matched.  */
+  char *translate;
+
+	/* Number of subexpressions found by the compiler.  */
+  size_t re_nsub;
+
+	/* Zero if this pattern cannot match the empty string, one else.
+	   Well, in truth it's used only in `re_search_2', to see
+	   whether or not we should use the fastmap, so we don't set
+	   this absolutely perfectly; see `re_compile_fastmap' (the
+	   `duplicate' case).  */
+  unsigned can_be_null : 1;
+
+	/* If REGS_UNALLOCATED, allocate space in the `regs' structure
+	     for `max (RE_NREGS, re_nsub + 1)' groups.
+	   If REGS_REALLOCATE, reallocate space if necessary.
+	   If REGS_FIXED, use what's there.  */
+#define REGS_UNALLOCATED 0
+#define REGS_REALLOCATE 1
+#define REGS_FIXED 2
+  unsigned regs_allocated : 2;
+
+	/* Set to zero when `regex_compile' compiles a pattern; set to one
+	   by `re_compile_fastmap' if it updates the fastmap.  */
+  unsigned fastmap_accurate : 1;
+
+	/* If set, `re_match_2' does not return information about
+	   subexpressions.  */
+  unsigned no_sub : 1;
+
+	/* If set, a beginning-of-line anchor doesn't match at the
+	   beginning of the string.  */
+  unsigned not_bol : 1;
+
+	/* Similarly for an end-of-line anchor.  */
+  unsigned not_eol : 1;
+
+	/* If true, an anchor at a newline matches.  */
+  unsigned newline_anchor : 1;
+
+/* [[[end pattern_buffer]]] */
+};
+
+typedef struct re_pattern_buffer regex_t;
+
+
+/* search.c (search_buffer) in Emacs needs this one opcode value.  It is
+   defined both in `regex.c' and here.  */
+#define RE_EXACTN_VALUE 1
+
+/* Type for byte offsets within the string.  POSIX mandates this.  */
+typedef int regoff_t;
+
+
+/* This is the structure we store register match data in.  See
+   regex.texinfo for a full description of what registers match.  */
+struct re_registers
+{
+  unsigned num_regs;
+  regoff_t *start;
+  regoff_t *end;
+};
+
+
+/* If `regs_allocated' is REGS_UNALLOCATED in the pattern buffer,
+   `re_match_2' returns information about at least this many registers
+   the first time a `regs' structure is passed.  */
+#ifndef RE_NREGS
+#define RE_NREGS 30
+#endif
+
+
+/* POSIX specification for registers.  Aside from the different names than
+   `re_registers', POSIX uses an array of structures, instead of a
+   structure of arrays.  */
+typedef struct
+{
+  regoff_t rm_so;  /* Byte offset from string's start to substring's start.  */
+  regoff_t rm_eo;  /* Byte offset from string's start to substring's end.  */
+} regmatch_t;
+
+/* Declarations for routines.  */
+
+/* To avoid duplicating every routine declaration -- once with a
+   prototype (if we are ANSI), and once without (if we aren't) -- we
+   use the following macro to declare argument types.  This
+   unfortunately clutters up the declarations a bit, but I think it's
+   worth it.  */
+
+#if __STDC__
+
+#define _RE_ARGS(args) args
+
+#else /* not __STDC__ */
+
+#define _RE_ARGS(args) ()
+
+#endif /* not __STDC__ */
+
+/* Sets the current default syntax to SYNTAX, and return the old syntax.
+   You can also simply assign to the `re_syntax_options' variable.  */
+extern reg_syntax_t re_set_syntax _RE_ARGS ((reg_syntax_t syntax));
+
+/* Compile the regular expression PATTERN, with length LENGTH
+   and syntax given by the global `re_syntax_options', into the buffer
+   BUFFER.  Return NULL if successful, and an error string if not.  */
+extern const char *re_compile_pattern
+  _RE_ARGS ((const char *pattern, int length,
+	     struct re_pattern_buffer *buffer));
+
+
+/* Compile a fastmap for the compiled pattern in BUFFER; used to
+   accelerate searches.  Return 0 if successful and -2 if was an
+   internal error.  */
+extern int re_compile_fastmap _RE_ARGS ((struct re_pattern_buffer *buffer));
+
+
+/* Search in the string STRING (with length LENGTH) for the pattern
+   compiled into BUFFER.  Start searching at position START, for RANGE
+   characters.  Return the starting position of the match, -1 for no
+   match, or -2 for an internal error.  Also return register
+   information in REGS (if REGS and BUFFER->no_sub are nonzero).  */
+extern int re_search
+  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string,
+	    int length, int start, int range, struct re_registers *regs));
+
+
+/* Like `re_search', but search in the concatenation of STRING1 and
+   STRING2.  Also, stop searching at index START + STOP.  */
+extern int re_search_2
+  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string1,
+	     int length1, const char *string2, int length2,
+	     int start, int range, struct re_registers *regs, int stop));
+
+
+/* Like `re_search', but return how many characters in STRING the regexp
+   in BUFFER matched, starting at position START.  */
+extern int re_match
+  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string,
+	     int length, int start, struct re_registers *regs));
+
+
+/* Relates to `re_match' as `re_search_2' relates to `re_search'.  */
+extern int re_match_2
+  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string1,
+	     int length1, const char *string2, int length2,
+	     int start, struct re_registers *regs, int stop));
+
+
+/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
+   ENDS.  Subsequent matches using BUFFER and REGS will use this memory
+   for recording register information.  STARTS and ENDS must be
+   allocated with malloc, and must each be at least `NUM_REGS * sizeof
+   (regoff_t)' bytes long.
+
+   If NUM_REGS == 0, then subsequent matches should allocate their own
+   register data.
+
+   Unless this function is called, the first search or match using
+   PATTERN_BUFFER will allocate its own register data, without
+   freeing the old data.  */
+extern void re_set_registers
+  _RE_ARGS ((struct re_pattern_buffer *buffer, struct re_registers *regs,
+	     unsigned num_regs, regoff_t *starts, regoff_t *ends));
+
+/* 4.2 bsd compatibility.  */
+extern char *re_comp _RE_ARGS ((const char *));
+extern int re_exec _RE_ARGS ((const char *));
+
+/* POSIX compatibility.  */
+extern int regcomp _RE_ARGS ((regex_t *preg, const char *pattern, int cflags));
+extern int regexec
+  _RE_ARGS ((const regex_t *preg, const char *string, size_t nmatch,
+	     regmatch_t pmatch[], int eflags));
+extern size_t regerror
+  _RE_ARGS ((int errcode, const regex_t *preg, char *errbuf,
+	     size_t errbuf_size));
+extern void regfree _RE_ARGS ((regex_t *preg));
+
+#endif /* not __REGEXP_LIBRARY_H__ */
+
+/*
+Local variables:
+make-backup-files: t
+version-control: t
+trim-versions-without-asking: nil
+End:
+*/
diff --git a/compat/snprintf.c b/compat/snprintf.c
index dbfc2d6b6..580966e56 100644
--- a/compat/snprintf.c
+++ b/compat/snprintf.c
@@ -1,12 +1,25 @@
 #include "../git-compat-util.h"
 
+/*
+ * The size parameter specifies the available space, i.e. includes
+ * the trailing NUL byte; but Windows's vsnprintf expects the
+ * number of characters to write without the trailing NUL.
+ */
+#ifndef SNPRINTF_SIZE_CORR
+#define SNPRINTF_SIZE_CORR 0
+#endif
+
 #undef vsnprintf
 int git_vsnprintf(char *str, size_t maxsize, const char *format, va_list ap)
 {
 	char *s;
-	int ret;
+	int ret = -1;
 
-	ret = vsnprintf(str, maxsize, format, ap);
+	if (maxsize > 0) {
+		ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, ap);
+		/* Windows does not NUL-terminate if result fills buffer */
+		str[maxsize-1] = 0;
+	}
 	if (ret != -1)
 		return ret;
 
@@ -20,7 +33,7 @@ int git_vsnprintf(char *str, size_t maxsize, const char *format, va_list ap)
 		if (! str)
 			break;
 		s = str;
-		ret = vsnprintf(str, maxsize, format, ap);
+		ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, ap);
 	}
 	free(s);
 	return ret;
diff --git a/connect.c b/connect.c
index e92af2973..574f42fa4 100644
--- a/connect.c
+++ b/connect.c
@@ -529,7 +529,7 @@ struct child_process *git_connect(int fd[2], const char *url_orig,
 		end = host;
 
 	path = strchr(end, c);
-	if (path) {
+	if (path && !has_dos_drive_prefix(end)) {
 		if (c == ':') {
 			protocol = PROTO_SSH;
 			*path++ = '\0';
diff --git a/date.c b/date.c
index 1a4eb87b0..35a52576c 100644
--- a/date.c
+++ b/date.c
@@ -6,7 +6,10 @@
 
 #include "cache.h"
 
-static time_t my_mktime(struct tm *tm)
+/*
+ * This is like mktime, but without normalization of tm_wday and tm_yday.
+ */
+time_t tm_to_time_t(const struct tm *tm)
 {
 	static const int mdays[] = {
 	    0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
@@ -67,7 +70,7 @@ static int local_tzoffset(unsigned long time)
 
 	t = time;
 	localtime_r(&t, &tm);
-	t_local = my_mktime(&tm);
+	t_local = tm_to_time_t(&tm);
 
 	if (t_local < t) {
 		eastwest = -1;
@@ -322,7 +325,7 @@ static int is_date(int year, int month, int day, struct tm *now_tm, time_t now,
 		if (!now_tm)
 			return 1;
 
-		specified = my_mktime(r);
+		specified = tm_to_time_t(r);
 
 		/* Be it commit time or author time, it does not make
 		 * sense to specify timestamp way into the future.  Make
@@ -572,7 +575,7 @@ int parse_date(const char *date, char *result, int maxlen)
 	}
 
 	/* mktime uses local timezone */
-	then = my_mktime(&tm);
+	then = tm_to_time_t(&tm);
 	if (offset == -1)
 		offset = (then - mktime(&tm)) / 60;
 
@@ -611,7 +614,7 @@ void datestamp(char *buf, int bufsize)
 
 	time(&now);
 
-	offset = my_mktime(localtime(&now)) - now;
+	offset = tm_to_time_t(localtime(&now)) - now;
 	offset /= 60;
 
 	date_string(now, offset, buf, bufsize);
diff --git a/exec_cmd.c b/exec_cmd.c
index 0f8f4b5b7..da04efe95 100644
--- a/exec_cmd.c
+++ b/exec_cmd.c
@@ -4,9 +4,42 @@
 #define MAX_ARGS	32
 
 extern char **environ;
-static const char *builtin_exec_path = GIT_EXEC_PATH;
 static const char *argv_exec_path;
 
+static const char *builtin_exec_path(void)
+{
+#ifndef __MINGW32__
+	return GIT_EXEC_PATH;
+#else
+	int len;
+	char *p, *q, *sl;
+	static char *ep;
+	if (ep)
+		return ep;
+
+	len = strlen(_pgmptr);
+	if (len < 2)
+		return ep = ".";
+
+	p = ep = xmalloc(len+1);
+	q = _pgmptr;
+	sl = NULL;
+	/* copy program name, turn '\\' into '/', skip last part */
+	while ((*p = *q)) {
+		if (*q == '\\' || *q == '/') {
+			*p = '/';
+			sl = p;
+		}
+		p++, q++;
+	}
+	if (sl)
+		*sl = '\0';
+	else
+		ep[0] = '.', ep[1] = '\0';
+	return ep;
+#endif
+}
+
 void git_set_argv_exec_path(const char *exec_path)
 {
 	argv_exec_path = exec_path;
@@ -26,7 +59,7 @@ const char *git_exec_path(void)
 		return env;
 	}
 
-	return builtin_exec_path;
+	return builtin_exec_path();
 }
 
 static void add_path(struct strbuf *out, const char *path)
@@ -37,7 +70,7 @@ static void add_path(struct strbuf *out, const char *path)
 		else
 			strbuf_addstr(out, make_absolute_path(path));
 
-		strbuf_addch(out, ':');
+		strbuf_addch(out, PATH_SEP);
 	}
 }
 
@@ -50,7 +83,7 @@ void setup_path(const char *cmd_path)
 
 	add_path(&new_path, argv_exec_path);
 	add_path(&new_path, getenv(EXEC_PATH_ENVIRONMENT));
-	add_path(&new_path, builtin_exec_path);
+	add_path(&new_path, builtin_exec_path());
 	add_path(&new_path, cmd_path);
 
 	if (old_path)
diff --git a/git-compat-util.h b/git-compat-util.h
index 6f94a8197..545df5924 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -63,17 +63,18 @@
 #include <sys/time.h>
 #include <time.h>
 #include <signal.h>
-#include <sys/wait.h>
 #include <fnmatch.h>
+#include <assert.h>
+#include <regex.h>
+#include <utime.h>
+#ifndef __MINGW32__
+#include <sys/wait.h>
 #include <sys/poll.h>
 #include <sys/socket.h>
 #include <sys/ioctl.h>
-#include <utime.h>
 #ifndef NO_SYS_SELECT_H
 #include <sys/select.h>
 #endif
-#include <assert.h>
-#include <regex.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <arpa/inet.h>
@@ -89,6 +90,10 @@
 #include <grp.h>
 #define _ALL_SOURCE 1
 #endif
+#else 	/* __MINGW32__ */
+/* pull in Windows compatibility stuff */
+#include "compat/mingw.h"
+#endif	/* __MINGW32__ */
 
 #ifndef NO_ICONV
 #include <iconv.h>
@@ -105,6 +110,22 @@
 #define PRIuMAX "llu"
 #endif
 
+#ifndef PATH_SEP
+#define PATH_SEP ':'
+#endif
+
+#ifndef STRIP_EXTENSION
+#define STRIP_EXTENSION ""
+#endif
+
+#ifndef has_dos_drive_prefix
+#define has_dos_drive_prefix(path) 0
+#endif
+
+#ifndef is_dir_sep
+#define is_dir_sep(c) ((c) == '/')
+#endif
+
 #ifdef __GNUC__
 #define NORETURN __attribute__((__noreturn__))
 #else
@@ -126,6 +147,7 @@ extern void set_error_routine(void (*routine)(const char *err, va_list params));
 extern void set_warn_routine(void (*routine)(const char *warn, va_list params));
 
 extern int prefixcmp(const char *str, const char *prefix);
+extern time_t tm_to_time_t(const struct tm *tm);
 
 #ifdef NO_MMAP
 
@@ -163,6 +185,12 @@ extern int git_munmap(void *start, size_t length);
 #define pread git_pread
 extern ssize_t git_pread(int fd, void *buf, size_t count, off_t offset);
 #endif
+/*
+ * Forward decl that will remind us if its twin in cache.h changes.
+ * This function is used in compat/pread.c.  But we can't include
+ * cache.h there.
+ */
+extern ssize_t read_in_full(int fd, void *buf, size_t count);
 
 #ifdef NO_SETENV
 #define setenv gitsetenv
diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index a44b1c74a..9cceb21a8 100755
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -142,3 +142,16 @@ then
 	}
 	: ${GIT_OBJECT_DIRECTORY="$GIT_DIR/objects"}
 fi
+
+# Fix some commands on Windows
+case $(uname -s) in
+*MINGW*)
+	# Windows has its own (incompatible) sort and find
+	sort () {
+		/usr/bin/sort "$@"
+	}
+	find () {
+		/usr/bin/find "$@"
+	}
+	;;
+esac
diff --git a/git.c b/git.c
index 22ac5226d..3307c078e 100644
--- a/git.c
+++ b/git.c
@@ -369,6 +369,16 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "pack-refs", cmd_pack_refs, RUN_SETUP },
 	};
 	int i;
+	static const char ext[] = STRIP_EXTENSION;
+
+	if (sizeof(ext) > 1) {
+		i = strlen(argv[0]) - strlen(ext);
+		if (i > 0 && !strcmp(argv[0] + i, ext)) {
+			char *argv0 = strdup(argv[0]);
+			argv[0] = cmd = argv0;
+			argv0[i] = '\0';
+		}
+	}
 
 	/* Turn "git cmd --help" into "git help cmd" */
 	if (argc > 1 && !strcmp(argv[1], "--help")) {
@@ -416,8 +426,8 @@ static void execv_dashed_external(const char **argv)
 
 int main(int argc, const char **argv)
 {
-	const char *cmd = argv[0] ? argv[0] : "git-help";
-	char *slash = strrchr(cmd, '/');
+	const char *cmd = argv[0] && *argv[0] ? argv[0] : "git-help";
+	char *slash = (char *)cmd + strlen(cmd);
 	const char *cmd_path = NULL;
 	int done_alias = 0;
 
@@ -426,7 +436,10 @@ int main(int argc, const char **argv)
 	 * name, and the dirname as the default exec_path
 	 * if we don't have anything better.
 	 */
-	if (slash) {
+	do
+		--slash;
+	while (cmd <= slash && !is_dir_sep(*slash));
+	if (cmd <= slash) {
 		*slash++ = 0;
 		cmd_path = cmd;
 		cmd = slash;
diff --git a/help.c b/help.c
index 5d1a773ad..ca9632b6c 100644
--- a/help.c
+++ b/help.c
@@ -391,6 +391,32 @@ static void pretty_print_string_list(struct cmdnames *cmds, int longest)
 	}
 }
 
+static int is_executable(const char *name)
+{
+	struct stat st;
+
+	if (stat(name, &st) || /* stat, not lstat */
+	    !S_ISREG(st.st_mode))
+		return 0;
+
+#ifdef __MINGW32__
+	/* cannot trust the executable bit, peek into the file instead */
+	char buf[3] = { 0 };
+	int n;
+	int fd = open(name, O_RDONLY);
+	st.st_mode &= ~S_IXUSR;
+	if (fd >= 0) {
+		n = read(fd, buf, 2);
+		if (n == 2)
+			/* DOS executables start with "MZ" */
+			if (!strcmp(buf, "#!") || !strcmp(buf, "MZ"))
+				st.st_mode |= S_IXUSR;
+		close(fd);
+	}
+#endif
+	return st.st_mode & S_IXUSR;
+}
+
 static unsigned int list_commands_in_dir(struct cmdnames *cmds,
 					 const char *path)
 {
@@ -404,15 +430,12 @@ static unsigned int list_commands_in_dir(struct cmdnames *cmds,
 		return 0;
 
 	while ((de = readdir(dir)) != NULL) {
-		struct stat st;
 		int entlen;
 
 		if (prefixcmp(de->d_name, prefix))
 			continue;
 
-		if (stat(de->d_name, &st) || /* stat, not lstat */
-		    !S_ISREG(st.st_mode) ||
-		    !(st.st_mode & S_IXUSR))
+		if (!is_executable(de->d_name))
 			continue;
 
 		entlen = strlen(de->d_name) - prefix_len;
@@ -447,7 +470,7 @@ static unsigned int load_command_list(void)
 
 	path = paths = xstrdup(env_path);
 	while (1) {
-		if ((colon = strchr(path, ':')))
+		if ((colon = strchr(path, PATH_SEP)))
 			*colon = 0;
 
 		len = list_commands_in_dir(&other_cmds, path);
diff --git a/pager.c b/pager.c
index dbd941421..6b5c9e44b 100644
--- a/pager.c
+++ b/pager.c
@@ -1,12 +1,13 @@
 #include "cache.h"
 
 /*
- * This is split up from the rest of git so that we might do
- * something different on Windows, for example.
+ * This is split up from the rest of git so that we can do
+ * something different on Windows.
  */
 
 static int spawned_pager;
 
+#ifndef __MINGW32__
 static void run_pager(const char *pager)
 {
 	/*
@@ -22,11 +23,31 @@ static void run_pager(const char *pager)
 	execlp(pager, pager, NULL);
 	execl("/bin/sh", "sh", "-c", pager, NULL);
 }
+#else
+#include "run-command.h"
+
+static const char *pager_argv[] = { "sh", "-c", NULL, NULL };
+static struct child_process pager_process = {
+	.argv = pager_argv,
+	.in = -1
+};
+static void wait_for_pager(void)
+{
+	fflush(stdout);
+	fflush(stderr);
+	/* signal EOF to pager */
+	close(1);
+	close(2);
+	finish_command(&pager_process);
+}
+#endif
 
 void setup_pager(void)
 {
+#ifndef __MINGW32__
 	pid_t pid;
 	int fd[2];
+#endif
 	const char *pager = getenv("GIT_PAGER");
 
 	if (!isatty(1))
@@ -45,6 +66,7 @@ void setup_pager(void)
 
 	spawned_pager = 1; /* means we are emitting to terminal */
 
+#ifndef __MINGW32__
 	if (pipe(fd) < 0)
 		return;
 	pid = fork();
@@ -72,6 +94,20 @@ void setup_pager(void)
 	run_pager(pager);
 	die("unable to execute pager '%s'", pager);
 	exit(255);
+#else
+	/* spawn the pager */
+	pager_argv[2] = pager;
+	if (start_command(&pager_process))
+		return;
+
+	/* original process continues, but writes to the pipe */
+	dup2(pager_process.in, 1);
+	dup2(pager_process.in, 2);
+	close(pager_process.in);
+
+	/* this makes sure that the parent terminates after the pager */
+	atexit(wait_for_pager);
+#endif
 }
 
 int pager_in_use(void)
diff --git a/run-command.c b/run-command.c
index 44100a749..2ce8c2b2f 100644
--- a/run-command.c
+++ b/run-command.c
@@ -65,21 +65,8 @@ int start_command(struct child_process *cmd)
 		cmd->err = fderr[0];
 	}
 
+#ifndef __MINGW32__
 	cmd->pid = fork();
-	if (cmd->pid < 0) {
-		if (need_in)
-			close_pair(fdin);
-		else if (cmd->in)
-			close(cmd->in);
-		if (need_out)
-			close_pair(fdout);
-		else if (cmd->out)
-			close(cmd->out);
-		if (need_err)
-			close_pair(fderr);
-		return -ERR_RUN_COMMAND_FORK;
-	}
-
 	if (!cmd->pid) {
 		if (cmd->no_stdin)
 			dup_devnull(0);
@@ -128,6 +115,88 @@ int start_command(struct child_process *cmd)
 		}
 		die("exec %s failed.", cmd->argv[0]);
 	}
+#else
+	int s0 = -1, s1 = -1, s2 = -1;	/* backups of stdin, stdout, stderr */
+	const char *sargv0 = cmd->argv[0];
+	char **env = environ;
+	struct strbuf git_cmd;
+
+	if (cmd->no_stdin) {
+		s0 = dup(0);
+		dup_devnull(0);
+	} else if (need_in) {
+		s0 = dup(0);
+		dup2(fdin[0], 0);
+	} else if (cmd->in) {
+		s0 = dup(0);
+		dup2(cmd->in, 0);
+	}
+
+	if (cmd->no_stderr) {
+		s2 = dup(2);
+		dup_devnull(2);
+	} else if (need_err) {
+		s2 = dup(2);
+		dup2(fderr[1], 2);
+	}
+
+	if (cmd->no_stdout) {
+		s1 = dup(1);
+		dup_devnull(1);
+	} else if (cmd->stdout_to_stderr) {
+		s1 = dup(1);
+		dup2(2, 1);
+	} else if (need_out) {
+		s1 = dup(1);
+		dup2(fdout[1], 1);
+	} else if (cmd->out > 1) {
+		s1 = dup(1);
+		dup2(cmd->out, 1);
+	}
+
+	if (cmd->dir)
+		die("chdir in start_command() not implemented");
+	if (cmd->env) {
+		env = copy_environ();
+		for (; *cmd->env; cmd->env++)
+			env = env_setenv(env, *cmd->env);
+	}
+
+	if (cmd->git_cmd) {
+		strbuf_init(&git_cmd, 0);
+		strbuf_addf(&git_cmd, "git-%s", cmd->argv[0]);
+		cmd->argv[0] = git_cmd.buf;
+	}
+
+	cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env);
+
+	if (cmd->env)
+		free_environ(env);
+	if (cmd->git_cmd)
+		strbuf_release(&git_cmd);
+
+	cmd->argv[0] = sargv0;
+	if (s0 >= 0)
+		dup2(s0, 0), close(s0);
+	if (s1 >= 0)
+		dup2(s1, 1), close(s1);
+	if (s2 >= 0)
+		dup2(s2, 2), close(s2);
+#endif
+
+	if (cmd->pid < 0) {
+		if (need_in)
+			close_pair(fdin);
+		else if (cmd->in)
+			close(cmd->in);
+		if (need_out)
+			close_pair(fdout);
+		else if (cmd->out)
+			close(cmd->out);
+		if (need_err)
+			close_pair(fderr);
+		return -ERR_RUN_COMMAND_FORK;
+	}
 
 	if (need_in)
 		close(fdin[0]);
@@ -219,13 +288,23 @@ int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const
 	return run_command(&cmd);
 }
 
+#ifdef __MINGW32__
+static __stdcall unsigned run_thread(void *data)
+{
+	struct async *async = data;
+	return async->proc(async->fd_for_proc, async->data);
+}
+#endif
+
 int start_async(struct async *async)
 {
 	int pipe_out[2];
 
 	if (pipe(pipe_out) < 0)
 		return error("cannot create pipe: %s", strerror(errno));
+	async->out = pipe_out[0];
 
+#ifndef __MINGW32__
 	async->pid = fork();
 	if (async->pid < 0) {
 		error("fork (async) failed: %s", strerror(errno));
@@ -236,16 +315,33 @@ int start_async(struct async *async)
 		close(pipe_out[0]);
 		exit(!!async->proc(pipe_out[1], async->data));
 	}
-	async->out = pipe_out[0];
 	close(pipe_out[1]);
+#else
+	async->fd_for_proc = pipe_out[1];
+	async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
+	if (!async->tid) {
+		error("cannot create thread: %s", strerror(errno));
+		close_pair(pipe_out);
+		return -1;
+	}
+#endif
 	return 0;
 }
 
 int finish_async(struct async *async)
 {
+#ifndef __MINGW32__
 	int ret = 0;
 
 	if (wait_or_whine(async->pid))
 		ret = error("waitpid (async) failed");
+#else
+	DWORD ret = 0;
+	if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
+		ret = error("waiting for thread failed: %lu", GetLastError());
+	else if (!GetExitCodeThread(async->tid, &ret))
+		ret = error("cannot get thread exit code: %lu", GetLastError());
+	CloseHandle(async->tid);
+#endif
 	return ret;
 }
diff --git a/run-command.h b/run-command.h
index debe3074b..5203a9ebb 100644
--- a/run-command.h
+++ b/run-command.h
@@ -76,7 +76,12 @@ struct async {
 	int (*proc)(int fd, void *data);
 	void *data;
 	int out;	/* caller reads from here and closes it */
+#ifndef __MINGW32__
 	pid_t pid;
+#else
+	HANDLE tid;
+	int fd_for_proc;
+#endif
 };
 
 int start_async(struct async *async);
diff --git a/setup.c b/setup.c
index 3b111ea7c..cc3fb380c 100644
--- a/setup.c
+++ b/setup.c
@@ -6,11 +6,17 @@ static int inside_work_tree = -1;
 
 static int sanitary_path_copy(char *dst, const char *src)
 {
-	char *dst0 = dst;
+	char *dst0;
 
-	if (*src == '/') {
+	if (has_dos_drive_prefix(src)) {
+		*dst++ = *src++;
+		*dst++ = *src++;
+	}
+	dst0 = dst;
+
+	if (is_dir_sep(*src)) {
 		*dst++ = '/';
-		while (*src == '/')
+		while (is_dir_sep(*src))
 			src++;
 	}
 
@@ -26,27 +32,24 @@ static int sanitary_path_copy(char *dst, const char *src)
 		 * (4) "../"          -- strip one, eat slash and continue.
 		 */
 		if (c == '.') {
-			switch (src[1]) {
-			case '\0':
+			if (!src[1]) {
 				/* (1) */
 				src++;
-				break;
-			case '/':
+			} else if (is_dir_sep(src[1])) {
 				/* (2) */
 				src += 2;
-				while (*src == '/')
+				while (is_dir_sep(*src))
 					src++;
 				continue;
-			case '.':
-				switch (src[2]) {
-				case '\0':
+			} else if (src[1] == '.') {
+				if (!src[2]) {
 					/* (3) */
 					src += 2;
 					goto up_one;
-				case '/':
+				} else if (is_dir_sep(src[2])) {
 					/* (4) */
 					src += 3;
-					while (*src == '/')
+					while (is_dir_sep(*src))
 						src++;
 					goto up_one;
 				}
@@ -54,11 +57,11 @@ static int sanitary_path_copy(char *dst, const char *src)
 		}
 
 		/* copy up to the next '/', and eat all '/' */
-		while ((c = *src++) != '\0' && c != '/')
+		while ((c = *src++) != '\0' && !is_dir_sep(c))
 			*dst++ = c;
-		if (c == '/') {
-			*dst++ = c;
-			while (c == '/')
+		if (is_dir_sep(c)) {
+			*dst++ = '/';
+			while (is_dir_sep(c))
 				c = *src++;
 			src--;
 		} else if (!c)
@@ -77,7 +80,7 @@ static int sanitary_path_copy(char *dst, const char *src)
 			if (dst <= dst0)
 				break;
 			c = *dst--;
-			if (c == '/') {
+			if (c == '/') {	/* MinGW: cannot be '\\' anymore */
 				dst += 2;
 				break;
 			}
@@ -126,10 +129,23 @@ const char *prefix_path(const char *prefix, int len, const char *path)
 const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
 {
 	static char path[PATH_MAX];
+#ifndef __MINGW32__
 	if (!pfx || !*pfx || is_absolute_path(arg))
 		return arg;
 	memcpy(path, pfx, pfx_len);
 	strcpy(path + pfx_len, arg);
+#else
+	char *p;
+	/* don't add prefix to absolute paths, but still replace '\' by '/' */
+	if (is_absolute_path(arg))
+		pfx_len = 0;
+	else
+		memcpy(path, pfx, pfx_len);
+	strcpy(path + pfx_len, arg);
+	for (p = path + pfx_len; *p; p++)
+		if (*p == '\\')
+			*p = '/';
+#endif
 	return path;
 }
 
@@ -364,6 +380,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
 	const char *gitdirenv;
 	const char *gitfile_dir;
 	int len, offset;
+	int minoffset = 0;
 
 	/*
 	 * Let's assume that we are in a git repository.
@@ -414,6 +431,8 @@ const char *setup_git_directory_gently(int *nongit_ok)
 
 	if (!getcwd(cwd, sizeof(cwd)-1))
 		die("Unable to read current working directory");
+	if (has_dos_drive_prefix(cwd))
+		minoffset = 2;
 
 	/*
 	 * Test in the following order (relative to the cwd):
@@ -446,7 +465,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
 		}
 		chdir("..");
 		do {
-			if (!offset) {
+			if (offset <= minoffset) {
 				if (nongit_ok) {
 					if (chdir(cwd))
 						die("Cannot come back to cwd");
@@ -455,7 +474,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
 				}
 				die("Not a git repository");
 			}
-		} while (cwd[--offset] != '/');
+		} while (offset > minoffset && cwd[--offset] != '/');
 	}
 
 	inside_git_dir = 0;
diff --git a/sha1_file.c b/sha1_file.c
index dd8327c94..2187e6cae 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -83,14 +83,18 @@ int get_sha1_hex(const char *hex, unsigned char *sha1)
 	return 0;
 }
 
+static inline int offset_1st_component(const char *path)
+{
+	if (has_dos_drive_prefix(path))
+		return 2 + (path[2] == '/');
+	return *path == '/';
+}
+
 int safe_create_leading_directories(char *path)
 {
-	char *pos = path;
+	char *pos = path + offset_1st_component(path);
 	struct stat st;
 
-	if (is_absolute_path(path))
-		pos++;
-
 	while (pos) {
 		pos = strchr(pos, '/');
 		if (!pos)
@@ -401,7 +405,7 @@ void prepare_alt_odb(void)
 	if (!alt) alt = "";
 
 	alt_odb_tail = &alt_odb_list;
-	link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);
+	link_alt_odb_entries(alt, alt + strlen(alt), PATH_SEP, NULL, 0);
 
 	read_info_alternates(get_object_directory(), 0);
 }
diff --git a/templates/Makefile b/templates/Makefile
index bda9d1350..9f3f1fc35 100644
--- a/templates/Makefile
+++ b/templates/Makefile
@@ -8,12 +8,12 @@ INSTALL ?= install
 TAR ?= tar
 RM ?= rm -f
 prefix ?= $(HOME)
-template_dir ?= $(prefix)/share/git-core/templates
+template_instdir ?= $(prefix)/share/git-core/templates
 # DESTDIR=
 
 # Shell quote (do not use $(call) to accommodate ancient setups);
 DESTDIR_SQ = $(subst ','\'',$(DESTDIR))
-template_dir_SQ = $(subst ','\'',$(template_dir))
+template_instdir_SQ = $(subst ','\'',$(template_instdir))
 
 all: boilerplates.made custom
 
@@ -46,6 +46,6 @@ clean:
 	$(RM) -r blt boilerplates.made
 
 install: all
-	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(template_dir_SQ)'
+	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(template_instdir_SQ)'
 	(cd blt && $(TAR) cf - .) | \
-	(cd '$(DESTDIR_SQ)$(template_dir_SQ)' && umask 022 && $(TAR) xf -)
+	(cd '$(DESTDIR_SQ)$(template_instdir_SQ)' && umask 022 && $(TAR) xf -)
diff --git a/transport.c b/transport.c
index 3ff851935..4145eed97 100644
--- a/transport.c
+++ b/transport.c
@@ -709,7 +709,8 @@ static int is_local(const char *url)
 {
 	const char *colon = strchr(url, ':');
 	const char *slash = strchr(url, '/');
-	return !colon || (slash && slash < colon);
+	return !colon || (slash && slash < colon) ||
+		has_dos_drive_prefix(url);
 }
 
 static int is_file(const char *url)
diff --git a/upload-pack.c b/upload-pack.c
index b46dd365e..9f82941f8 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -135,6 +135,8 @@ static int do_rev_list(int fd, void *create_full_pack)
 		die("revision walk setup failed");
 	mark_edges_uninteresting(revs.commits, &revs, show_edge);
 	traverse_commit_list(&revs, show_commit, show_object);
+	fflush(pack_pipe);
+	fclose(pack_pipe);
 	return 0;
 }
 
diff --git a/write_or_die.c b/write_or_die.c
index 630be4cb9..e4c8e225f 100644
--- a/write_or_die.c
+++ b/write_or_die.c
@@ -34,7 +34,12 @@ void maybe_flush_or_die(FILE *f, const char *desc)
 			return;
 	}
 	if (fflush(f)) {
-		if (errno == EPIPE)
+		/*
+		 * On Windows, EPIPE is returned only by the first write()
+		 * after the reading end has closed its handle; subsequent
+		 * write()s return EINVAL.
+		 */
+		if (errno == EPIPE || errno == EINVAL)
 			exit(0);
 		die("write failure on %s: %s", desc, strerror(errno));
 	}