e3e168f629
and links exist:
${ntpd_chrootdir}/dev/clockctl
/var/db/ntp.drift -> ${ntpd_chrootdir}/var/db/ntp.drift
and then start ntpd with the appropriate options to run chroot(2)ed
under $ntpd_chrootdir as user ntpd group ntpd.
to take advantage of this, set ntpd_chrootdir in /etc/rc.conf.
[this is based on similar work i did for rc.d/named]