When rc.d/ntpd sets up ntpd to run in a chroot, it currently makes a convenience symlink for /var/db/ntp.drift. Unfortunately, our default driftfile name is actually ntpd.drift. Further complicating matters, users can change the name and location of the file by overriding ntpd_flags in rc.conf.
This loops through all the options in ntpd_flags, and for each one that names a file or directory, it makes the corresponding inside<->outside convenience symlink. It silently ignores any errors making the links, since they're just for convenience and things like readonly filesystems could be involved.