Tracking local port hacks?

[Rob Ellis]

We sometimes find it necessary to make some small change to
a port before installing it, and need a way to track/merge
these changes as ports are updated. Is there a recommended
way of doing that?

The cvsup faq (http://www.cvsup.org) suggests that it's
possible to get sources in "cvs mode" and it has some
suggestions for managing a local branch. Is that the best
way to do it? Anyone know how BIG the ports tree is if we
get it via cvsup in "cvs mode"?

Thanks.

- Rob