syslogd has an `altlog_proglist` stanza, which can place the log socket into a program's chroot directory, so it can still log.
This patch adds an equivalent to that for jails.
If used with jails, we lookup the each jail's "path" with `jls` appending it to the sockfile and, now also privsockfile.
Caveat: syslogd must be restarted before the jail is fully up