Define _GNU_SOURCE when using GCC

dracc · dracc · commit 2396a2e6da1c · 2019-05-01T14:42:39.000+02:00
Silences an asprintf() warning.
diff --git a/extract-xiso.c b/extract-xiso.c
@@ -237,6 +237,9 @@
 #if defined( __LINUX__ )
 	#define _LARGEFILE64_SOURCE
 #endif
+#if defined( __GNUC__ )
+	#define _GNU_SOURCE
+#endif
 
 
 #include <time.h>
