1 files changed, 3 insertions, 2 deletions
diff --git a/xmalloc.c b/xmalloc.c
index 75319ff..368e18d 100644
--- a/xmalloc.c
+++ b/xmalloc.c
@@ -4,8 +4,9 @@
  * Copyright 2014, 2015 Tobias Klauser
  * Subject to the GPL, version 2.
  */
-
-#define _GNU_SOURCE
+#ifndef _GNU_SOURCE
+# define _GNU_SOURCE
+#endif
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>