Make sure we have the vsscanf() prototype (thanks, Ozkan!). issue seen with glibc-2.8. Fixes Bugzilla #2721.
diff --git a/src/stdlib/SDL_string.c b/src/stdlib/SDL_string.c
index 5c343bb..68d88ec 100644
--- a/src/stdlib/SDL_string.c
+++ b/src/stdlib/SDL_string.c
@@ -23,6 +23,10 @@
#define SDL_DISABLE_ANALYZE_MACROS 1
#endif
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#endif
+
#include "../SDL_internal.h"
/* This file contains portable string manipulation functions for SDL */