Fixed build

src/video/uikit/SDL_uikitmodes.m

@@ -23,6 +23,7 @@
 #if SDL_VIDEO_DRIVER_UIKIT
 
 #include "SDL_assert.h"
+#include "SDL_system.h"
 #include "SDL_uikitmodes.h"
 
 #include "../../events/SDL_events_c.h"