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 macOS (previously Mac OS X and OS X), use Homebrew to install the proper headers:

brew install postgresql

and then running

gem install pg

should work.

Alternatively, instead of installing the whole postgresql, you can brew install libpq and export the correct PATH and PKG_CONFIG_PATH as explained in the 'Caveats' section