Fixed default libpatttern on Darwin, imported from prefix overlay.
Got merged upstream:
https://savannah.gnu.org/bugs/?37197
--- default.c.orig	2009-05-02 12:25:24 +0200
+++ default.c	2009-05-02 12:25:58 +0200
@@ -509,7 +509,11 @@
 #ifdef __MSDOS__
     ".LIBPATTERNS", "lib%.a $(DJDIR)/lib/lib%.a",
 #else
+#ifdef __APPLE__
+    ".LIBPATTERNS", "lib%.dylib lib%.a",
+#else
     ".LIBPATTERNS", "lib%.so lib%.a",
+#endif
 #endif
 #endif