NOTE_FORK
KASSERT((hint & (NOTE_EXEC | NOTE_EXIT | NOTE_FORK)) == 0);
kn->kn_fflags |= (kn->kn_sfflags & NOTE_FORK);
event[0].fflags = NOTE_EXIT | NOTE_FORK | NOTE_EXEC; /* | NOTE_TRACK;*/
want = NOTE_EXIT | NOTE_FORK | NOTE_EXEC;
if (event[0].fflags & NOTE_FORK) {
want &= ~NOTE_FORK;
EV_SET(&ke, (uintptr_t)pid, EVFILT_PROC, EV_ADD, NOTE_FORK|NOTE_TRACK,
ATF_REQUIRE((event.fflags & NOTE_FORK) == 0);