ax25_fillin_cb
void ax25_fillin_cb(ax25_cb *, ax25_dev *);
ax25_fillin_cb(ax25, ax25_dev);
ax25_fillin_cb(ax25, NULL);
ax25_fillin_cb(ax25, ax25->ax25_dev);
ax25_fillin_cb(ax25, ax25_dev);
ax25_fillin_cb(ax25, ax25_dev);