Update fullscreen and mode on Darwin to match window

This should normalize everything, with the possible exception of
"zoom" (the thing other OSs call maximized).  Ideally, we wouldn't
allow window size changes when "zoomed" if we could detect the state,
but it doesn't look like we can.

src/conio/sdl_con.c

@@ -1039,10 +1039,16 @@ void sdl_video_event_thread(void *data)
 				break;
 			case SDL_WINDOWEVENT:
 				switch(ev.window.event) {
-					case SDL_WINDOWEVENT_SIZE_CHANGED:
-						// SDL2: User resized window
 					case SDL_WINDOWEVENT_MAXIMIZED:
 					case SDL_WINDOWEVENT_RESTORED:
+#if defined(__DARWIN__)
+						fullscreen = (sdl.GetWindowFlags(win) & SDL_WINDOW_MAXIMIZED) != 0;
+						cio_api.mode=fullscreen?CIOLIB_MODE_SDL_FULLSCREEN:CIOLIB_MODE_SDL;
+						update_cvstat(vs);
+#endif
+						// Fall-through
+					case SDL_WINDOWEVENT_SIZE_CHANGED:
+						// SDL2: User resized window
 					case SDL_WINDOWEVENT_RESIZED:
 						pthread_mutex_lock(&sdl_mode_mutex);
 						if (sdl_mode) {