diff --git a/compositor/compositor-drm.c b/compositor/compositor-drm.c
index 78c33b31..10ba65a0 100644
--- a/compositor/compositor-drm.c
+++ b/compositor/compositor-drm.c
@@ -16,6 +16,8 @@
  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
+#define _GNU_SOURCE
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>