PostgreSQL 3?  There must be some sort of mistake here,
unless you're using an ancient version.

The current active versions of PostgreSQL are 6.21 and 6.3.
If you're having trouble with compiling PHP with either of them
please resubmit a bug report detailing exactly what goes
wrong ('cannot compile' is useless when trying to resolve
the problem - on the other hand, a copy&paste of the
compile failure is very useful).
If you're actually using a different version than 6.2x
or 6.3 - it's not supported.