Win32: fix potential multi-threading issue

...by removing a static buffer in do_stat_internal.

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Stepan Kasal <kasal@ucw.cz>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

compat/mingw.c

@@ -441,7 +441,7 @@ static int do_lstat(int follow, const char *file_name, struct stat *buf)
 static int do_stat_internal(int follow, const char *file_name, struct stat *buf)
 {
 	int namelen;
-	static char alt_name[PATH_MAX];
+	char alt_name[PATH_MAX];
 
 	if (!do_lstat(follow, file_name, buf))
 		return 0;