Just a note for those who looks for info on Gentoo & PostgreSQL (like I did today):
yes, as you might be already suspecting, PostgreSQL has been split
[STRIKEOUT:yes, there's a little howto] there was one. Just install dev-db/postgresql-base (if you don't need server; also it's a dep for lots of packages, for example, those with USE="postgres") or dev-db/postgresql-server (PostgreSQL server)
Got stable now, old-style packages are masked and will be removed.