MSGBUF_NEEDNL
mbp->msg_flags |= MSGBUF_NEEDNL;
if (mbp->msg_lastpri != pri && (mbp->msg_flags & MSGBUF_NEEDNL) != 0) {
mbp->msg_flags &= ~MSGBUF_NEEDNL;
if ((mbp->msg_flags & MSGBUF_NEEDNL) == 0 && prefix_len != 0) {
(mbp->msg_flags & MSGBUF_NEEDNL) == 0) {
mbp->msg_flags &= ~MSGBUF_NEEDNL;
mbp->msg_flags |= MSGBUF_NEEDNL;