diff --git a/include/chameleon.h b/include/chameleon.h
index 12c295a7732ef73f1a1fac421bb38be6f0cdd9ea..7aeaf7d331227c35cd34288db6a95b68fc50f2fc 100644
--- a/include/chameleon.h
+++ b/include/chameleon.h
@@ -30,7 +30,6 @@
  * CHAMELEON types and constants
  */
 #include "chameleon/config.h"
-#define _GNU_SOURCE 1
 #include <stdio.h>
 #include "chameleon/constants.h"
 #include "chameleon/types.h"