so_acceptq_dequeue
extern int so_acceptq_dequeue(struct sonode *, boolean_t,
if ((error = so_acceptq_dequeue(so, (fflag & (FNONBLOCK|FNDELAY)),
error = so_acceptq_dequeue(so, (fflag & (FNONBLOCK|FNDELAY)), nsop);
error = so_acceptq_dequeue(lso, (fflag & (FNONBLOCK|FNDELAY)), &nso);