The postgresql tarball includes "libpg-fe.h", but it isn't found in any of the RH7 postgresql RPMs. Unless you go manually extract and install the libpg-fe.h from the postgresql tarball you can't compile. The perl Postgresql DBD driver, and the mod_auth_psql Apache authentication module among other software. Dax Kelson Guru Labs
You're probably thinking of libpq-fe.h ("q", not "g") which is part of postgresql-devel. The postgresql DBD builds just fine, and is part of the current tree coming soon to a Rawhide near you.