[Bug other/109293] [12/13 Regression] Missing memmem() prototype in fixincludes/fixfixes.c on Windows/MinGW-W64

["pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109293

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Something like this:
diff --git a/fixincludes/configure.ac b/fixincludes/configure.ac
index 14813b910f1..00aeb1ce1d9 100644
--- a/fixincludes/configure.ac
+++ b/fixincludes/configure.ac
@@ -89,6 +89,7 @@ define(fixincludes_UNLOCKED_FUNCS, clearerr_unlocked
feof_unlocked dnl
   putchar_unlocked putc_unlocked)
 AC_CHECK_FUNCS(fixincludes_UNLOCKED_FUNCS)
 AC_CHECK_DECLS([abort, asprintf, basename(char *), errno, vasprintf])
+AC_CHECK_DECLS([memmem])
 AC_CHECK_DECLS(m4_split(m4_normalize(fixincludes_UNLOCKED_FUNCS)))

 # Checks for typedefs, structures, and compiler characteristics.
diff --git a/fixincludes/system.h b/fixincludes/system.h
index dca5d57b2e3..f7bbd0e952c 100644
--- a/fixincludes/system.h
+++ b/fixincludes/system.h
@@ -209,6 +209,11 @@ extern int errno;
 extern void abort (void);
 #endif

+#if defined (HAVE_DECL_MEMMEM) && !HAVE_DECL_MEMMEM
+extern void *memmem (const void *, size_t, const void *, size_t);
+#endif
+
+
 #if HAVE_SYS_STAT_H
 # include <sys/stat.h>
 #endif