+#ifdef USE_SDL_LIBRARY
+extern SDL_Surface *sdl_window;
+extern SDL_Surface *sdl_drawto, *sdl_drawto_field;
+extern SDL_Surface *sdl_backbuffer, *sdl_fieldbuffer;
+extern SDL_Surface *sdl_pix[];
+extern SDL_Surface *sdl_pix_masked[], *sdl_tile_masked[];
+#endif
+