p_sigcatch
kp->kp_sigcatch = p->p_sigcatch; /* p_sigacts-> */
if (SIGISMEMBER(p->p_sigcatch, sig))
SIGDELSET(p->p_sigcatch, sig);
SIGDELSET(p->p_sigcatch, sig);
SIGDELSET(p->p_sigcatch, sig);
SIGADDSET(p->p_sigcatch, sig);
while (SIGNOTEMPTY(p->p_sigcatch)) {
sig = sig_ffs(&p->p_sigcatch);
SIGDELSET(p->p_sigcatch, sig);
if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) &&
SIGDELSET(p->p_sigcatch, sig);