Provide a script from which to start krb5kdc through /etc/rc.d/kdc.
Simply add kdc_enable="YES" and kdc_program="/usr/local/sbin/kdc"
to /etc/rc.d. The script removes the Heimdal kdc --detach argument
prior to invoking krb5kdc.

The other approach that was considered was to replace getopt() in
kdc/main.c with getopt_long() however this approach was considered too
intrusive.