diff --git a/exec/ipc.c b/exec/ipc.c
index 17d721b3..41552214 100644
--- a/exec/ipc.c
+++ b/exec/ipc.c
@@ -32,6 +32,9 @@
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  */
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE 1
+#endif
 #include <pthread.h>
 #include <assert.h>
 #include <pwd.h>