fix missing volatile qualifier on lock in __get_locale

src/locale/locale_map.c

@@ -26,7 +26,7 @@ static const char envvars[][12] = {
 
 const struct __locale_map *__get_locale(int cat, const char *val)
 {
-	static int lock[2];
+	static volatile int lock[2];
 	static void *volatile loc_head;
 	const struct __locale_map *p;
 	struct __locale_map *new = 0;