The CVS head runs with PG 7.2 but you're probably best off with PG 7.1.3 if you want to use the 4.6 tarball. I think we may require 7.2 for 4.6 but that remains to be seen (7.2's been out for months). I think we'll definitely recommend it even if we don't require it because 7.2 has some significant improvements over 7.1, including many bug fixes.