PSL_TRACEFORK
return (p->p_slflag & (PSL_TRACEFORK|PSL_TRACED)) ==
(PSL_TRACEFORK|PSL_TRACED) && (flags & FORK_PPWAIT) == 0;
pe.pe_set_event = ISSET(t->p_slflag, PSL_TRACEFORK) ?
SET(t->p_slflag, PSL_TRACEFORK);
CLR(t->p_slflag, PSL_TRACEFORK);