OPT_NAT
opts |= OPT_NAT;
if ((opts & OPT_NAT) == 0)
} else if ((opts & (OPT_BRIEF|OPT_NAT)) ==
(OPT_NAT|OPT_BRIEF)) {
if ((opts & (OPT_BRIEF|OPT_NAT)) != (OPT_NAT|OPT_BRIEF))