Tested as a dendency of dev-python/django. Build process complete without errors
Created attachment 123111 [details] dev-python/psycopg ebuild
psycopq is already in the tree: http://overlays.gentoo.org/proj/alt/browser/trunk/prefix-overlay/dev-python/psycopg/psycopg-2.0.5.1.ebuild
do you want it having a ~x86-macos keyword, perhaps?
marked ~x86-macos. (already in portage)