Allow background input when testing game controllers

test/testgamecontroller.c

@@ -425,6 +425,7 @@ main(int argc, char *argv[])
 
     SDL_SetHint(SDL_HINT_ACCELEROMETER_AS_JOYSTICK, "0");
     SDL_SetHint(SDL_HINT_JOYSTICK_HIDAPI_PS4_RUMBLE, "1");
+    SDL_SetHint(SDL_HINT_JOYSTICK_ALLOW_BACKGROUND_EVENTS, "1");
 
     /* Enable standard application logging */
     SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);