Fix various sparse warnings in the git source code

There are a few remaining ones, but this fixes the trivial ones. It boils
down to two main issues that sparse complains about:

 - warning: Using plain integer as NULL pointer

   Sparse doesn't like you using '0' instead of 'NULL'. For various good
   reasons, not the least of which is just the visual confusion. A NULL
   pointer is not an integer, and that whole "0 works as NULL" is a
   historical accident and not very pretty.

   A few of these remain: zlib is a total mess, and Z_NULL is just a 0.
   I didn't touch those.

 - warning: symbol 'xyz' was not declared. Should it be static?

   Sparse wants to see declarations for any functions you export. A lack
   of a declaration tends to mean that you should either add one, or you
   should mark the function 'static' to show that it's in file scope.

   A few of these remain: I only did the ones that should obviously just
   be made static.

That 'wt_status_submodule_summary' one is debatable. It has a few related
flags (like 'wt_status_use_color') which _are_ declared, and are used by
builtin-commit.c. So maybe we'd like to export it at some point, but it's
not declared now, and not used outside of that file, so 'static' it is in
this patch.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/mailmap.c b/mailmap.c
index bb1f2fb71..f167c005b 100644
--- a/mailmap.c
+++ b/mailmap.c
@@ -103,7 +103,7 @@ static char *parse_name_and_email(char *buffer, char **name,
 		char **email, int allow_empty_email)
 {
 	char *left, *right, *nstart, *nend;
-	*name = *email = 0;
+	*name = *email = NULL;
 
 	if ((left = strchr(buffer, '<')) == NULL)
 		return NULL;
@@ -136,7 +136,7 @@ static int read_single_mailmap(struct string_list *map, const char *filename, ch
 	if (f == NULL)
 		return 1;
 	while (fgets(buffer, sizeof(buffer), f) != NULL) {
-		char *name1 = 0, *email1 = 0, *name2 = 0, *email2 = 0;
+		char *name1 = NULL, *email1 = NULL, *name2 = NULL, *email2 = NULL;
 		if (buffer[0] == '#') {
 			static const char abbrev[] = "# repo-abbrev:";
 			int abblen = sizeof(abbrev) - 1;
@@ -200,7 +200,7 @@ int map_user(struct string_list *map,
 	if (!p) {
 		/* email passed in might not be wrapped in <>, but end with a \0 */
 		p = memchr(email, '\0', maxlen_email);
-		if (p == 0)
+		if (!p)
 			return 0;
 	}
 	if (p - email + 1 < sizeof(buf))