diff -u a/gdk/macos/gdkmacoseventsource-private.h b/gdk/macos/gdkmacoseventsource-private.h
--- a/gdk/macos/gdkmacoseventsource-private.h
+++ b/gdk/macos/gdkmacoseventsource-private.h
@@ -24,6 +24,8 @@

 #include "gdkmacosdisplay.h"

+#include "gdk-private.h"
+
 G_BEGIN_DECLS

 typedef enum