cornishbeaver I've never used
xdm so, you'll have to wait for people that do, @JuvenalUrbino but, I can say that
hal no longer exists in pkgsrc.
The instructions you've been following are over 7 years old.
What happens if you remove
xdm and use
Honestly, I've never used xfce but, I know people do use it. On the other hand, I co-maintain LXQt, so that one I know how to set-up.