diff --git a/shared/os-compatibility.c b/shared/os-compatibility.c
index 21d4d02..4f96dd4 100644
--- a/shared/os-compatibility.c
+++ b/shared/os-compatibility.c
@@ -20,7 +20,7 @@
  * OF THIS SOFTWARE.
  */
 
-#define _GNU_SOURCE
+#include "config.h"
 
 #include <sys/types.h>
 #include <sys/socket.h>