diff --git a/src/uv-unix.c b/src/uv-unix.c
index 2ee2f864..116411db 100644
--- a/src/uv-unix.c
+++ b/src/uv-unix.c
@@ -18,12 +18,12 @@
  * IN THE SOFTWARE.
  */
 
+#define _GNU_SOURCE /* O_CLOEXEC, accept4(), etc. */
+
 #include "uv.h"
 #include "uv-common.h"
 #include "uv-eio.h"
 
-#define _GNU_SOURCE /* O_CLOEXEC */
-
 #include <stddef.h> /* NULL */
 #include <stdio.h> /* printf */
 #include <stdlib.h>