As for the X server, I don't know I compiled the whole X.org from that git repository about a month ago and got 7.1.99.<something> with a release date of december 2005. Maybe the version from git isn't cleaned up? (but it may be up to date now).
There is an announcement on wiki.x.org:
Development snapshots are currently on hiatus. Most modules now update slowly enough that frequent snapshots aren't needed. The server itself is still quite volatile; snapshots of it will probably resume shortly.
Why do you want to compile from git anyway? Is there some specific feature that you want, or do you just want to have the latest and (not so) greatest? Keep in mind that developers may not account for changes in the development version, and you'll end up with "bleeding edge" that breaks things..