diff --git a/src/lock/lock.c b/src/lock/lock.c
index fd50c40..1f5f2de 100644
--- a/src/lock/lock.c
+++ b/src/lock/lock.c
@@ -3,6 +3,7 @@
  *
  * Copyright (C) 2010 Creytiv.com
  */
+#define _DEFAULT_SOURCE 1
 #define __USE_UNIX98 1
 #include <pthread.h>
 #include <re_types.h>