add: if (ao_driver == NULL) ao_driver = xine_open_audio_driver (gtx->priv->xine, NULL, NULL);  g_free (audio_driver_id);  return ao_driver;
context: load_audio_out_driver (GtkXine *gtx, const char *audio_driver_id){	if (strcmp (audio_driver_id, "null") == 0)		return NULL;	return xine_open_audio_driver (gtx->priv->xine,			audio_driver_id, NULL);}