Can't find the 'libpq-fe.h header when trying to install pg gem

Question

I am using the Ruby on Rails 3.1 pre version. I like to use PostgreSQL, but the problem is installing the pg gem. It gives me the following error:

Answer 1

On FreeBSD (9.1) the necessary package is /usr/ports/database/postgresql-server* which when installed will also install the required header file that makes the gem install of "pg" fail. This answer here helped me find the solution but the difference in package names required a bit of searching.

Hopefully this helps someone avoid a bit of head scratching when searching for the "-dev" package on a FreeBSD system!