Exit of SDL_WaitEvent() returns an error.

It doesn't appear recoverable, but instead only spams the commandline.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30482 a1c6a512-1295-4272-9138-f99709370657

firmware/target/hosted/sdl/button-sdl.c

@@ -292,8 +292,10 @@ void gui_message_loop(void)
 
     do {
         /* wait for the next event */
-        while(SDL_WaitEvent(&event) == 0)
+        if(SDL_WaitEvent(&event) == 0) {
             printf("SDL_WaitEvent() error\n");
+            return; /* error, out of here */
+        }
 
         sim_enter_irq_handler();
         quit = event_handler(&event);