cvsup

I've been trying to set up a cvsup mirror following the instructions at 
http://developer.postgresql.org/docs/postgres/cvsup.html

However, it seems to be awry w.r.t. the earthdistance module. Could some 
kind person please tell me what needs to be done in either the cvsup 
config or the modules file or both, so that "cvs co -p pgsql" works nicely?

If done as an update to the docs that would be especially nice :-) But 
if not, I'll do the docs once I get it working.

cheers

andrew