diff --git a/engine/common/crashhandler.c b/engine/common/crashhandler.c
index 3c638b47..64c537c1 100644
--- a/engine/common/crashhandler.c
+++ b/engine/common/crashhandler.c
@@ -12,7 +12,9 @@ but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 */
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 
 #include "common.h"