main: SDL_AppQuit() now reports the result value.

Fixes #10994.

test/testcamera.c

@@ -353,7 +353,7 @@ SDL_AppResult SDL_AppIterate(void *appstate)
     return SDL_APP_CONTINUE;
 }
 
-void SDL_AppQuit(void *appstate)
+void SDL_AppQuit(void *appstate, SDL_AppResult result)
 {
     SDL_ReleaseCameraFrame(camera, frame_current);
     SDL_CloseCamera(camera);