test: use SDL_HINT_(AUDIO,VIDEO)_DRIVER macro

test/testoffscreen.c

@@ -109,7 +109,7 @@ int main(int argc, char *argv[])
     }
 
     /* Force the offscreen renderer, if it cannot be created then fail out */
-    SDL_SetHint("SDL_VIDEO_DRIVER", "offscreen");
+    SDL_SetHint(SDL_HINT_VIDEO_DRIVER, "offscreen");
     if (SDL_InitSubSystem(SDL_INIT_VIDEO) < 0) {
         SDL_Log("Couldn't initialize the offscreen video driver: %s\n",
                 SDL_GetError());