chgptscnt
chgptscnt(psc->pts_cred->cr_ruidinfo, -1, 0);
ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
chgptscnt(cred->cr_ruidinfo, -1, 0);
ok = chgptscnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_NPTS));
int chgptscnt(struct uidinfo *uip, int diff, rlim_t maxval);