Added note that the #ifdef is for !__IOS__

src/main/generic/SDL_sysmain_callbacks.c

@@ -80,4 +80,4 @@ int SDL_EnterAppMainCallbacks(int argc, char* argv[], SDL_AppInit_func appinit,
     return (rc < 0) ? 1 : 0;
 }
 
-#endif
+#endif // !__IOS__