ARC4_ENTR_HAVE
(void)atomic_cmpset_int(&arc4rand_iniseed_state, ARC4_ENTR_NONE, ARC4_ENTR_HAVE);
(arc4rand_iniseed_state == ARC4_ENTR_HAVE &&
atomic_cmpset_int(&arc4rand_iniseed_state, ARC4_ENTR_HAVE, ARC4_ENTR_SEED))))