diff --git a/src/stdafx.h b/src/stdafx.h
--- a/src/stdafx.h
+++ b/src/stdafx.h
@@ -145,11 +145,6 @@
 	#include <malloc.h> // alloca()
 #endif
 
-#if defined(__MINGW32__) && defined(_GNU_SOURCE)
-	/* For some weird reasons, SDL defines _GNU_SOURCE */
-	#undef _GNU_SOURCE
-#endif
-
 #if defined(WIN32)
 	#define WIN32_LEAN_AND_MEAN     // Exclude rarely-used stuff from Windows headers
 #endif