diff --git a/src/video/wayland/SDL_waylanddatamanager.c b/src/video/wayland/SDL_waylanddatamanager.c
index 809494762..afcec1a99 100644
--- a/src/video/wayland/SDL_waylanddatamanager.c
+++ b/src/video/wayland/SDL_waylanddatamanager.c
@@ -23,8 +23,10 @@
 
 #if SDL_VIDEO_DRIVER_WAYLAND
 
-#include <unistd.h>
+/* _GNU_SOURCE for pipe2 declaration. */
+#define _GNU_SOURCE
 #include <fcntl.h>
+#include <unistd.h>
 #include <limits.h>
 #include <signal.h>