The recent minor alteration to if_sl.c is not the source of the problem.

It seems that the following conditional in sloutput() in if_sl.c is
succeeding, causing sloutput() to return EHOSTUNREACH:

            if ((sc->sc_ttyp->t_state & TS_CARR_ON) == 0 &&
                (sc->sc_ttyp->t_cflag & CLOCAL) == 0) {
                m_freem(m);
                return (EHOSTUNREACH);
            }

I'm not sure why t_state and t_cflag are both zero; even with the following
line in my /etc/ttys, the above conditional still causes sloutput() to return
EHOSTUNREACH:

tty01	"/usr/libexec/getty std.38400"	unknown off secure local rtscts softcar

Now "ttyflags -a" IS executed in my /etc/rc, so these flags should be set.
Perhaps the com driver unsets, or fails to set, these flags.
I have rummaged around in com.c but haven't been able to find the problem
yet.  Could someone with more understanding of the inner workings of com.c
take a look at it?

Thanks,
Glenn