diff --git a/load.c b/load.c
index 6d1c6ed..adc0af5 100644
--- a/load.c
+++ b/load.c
@@ -8,6 +8,7 @@
  * This file is released under the GPLv2.
  */

+#define _GNU_SOURCE
 #include "config.h"
 #include <sys/types.h>
 #include <sys/stat.h>
diff --git a/suspend.c b/suspend.c
index 479ce58..c82a85f 100644
--- a/suspend.c
+++ b/suspend.c
@@ -9,6 +9,7 @@
  *
  */

+#define _GNU_SOURCE
 #include "config.h"
 #include <sys/types.h>
 #include <sys/stat.h>
diff --git a/swsusp.h b/swsusp.h
index 2aae184..8d22b92 100644
--- a/swsusp.h
+++ b/swsusp.h
@@ -9,6 +9,7 @@
  *
  */

+#define _GNU_SOURCE
 #include <stdint.h>
 #include <linux/fs.h>
 #include <linux/suspend_ioctls.h>