I suspect this issue is a variation of the issue reported in #474515 for postgresql-8.3 "does not handle duplicate provides". In that BTS report, ideas for a solution is posted.
Happy hacking, -- Petter Reinholdtsen -- To UNSUBSCRIBE, email to debian-bugs-rc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org