engine: platform: sdl: don't enable high dpi code for Apple

It seems enables HighDPI awareness but doesn't create HighDPI OpenGL context
It needs some plist magic to be enabled back again

engine/platform/sdl/vid_sdl.c

@@ -553,7 +553,9 @@ static qboolean VID_SetScreenResolution( int width, int height )
 	Uint32 wndFlags = 0;
 	static string wndname;
 
+#if !XASH_APPLE
 	if( vid_highdpi->value ) wndFlags |= SDL_WINDOW_ALLOW_HIGHDPI;
+#endif
 	Q_strncpy( wndname, GI->title, sizeof( wndname ));
 
 	want.w = width;