I'm suddenly running into this issue when running 'bundle install'. Everything seems to be installing correctly, but then I run into an issue with 'pg', as so many others seem to do. As the message says, I try running 'gem install pg - '0.12.2'' but it still fails.
I'm on Snow Leopard 10.6 and this is the error I'm getting:
Installing pg (0.12.2) with native extensions
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
/Users/thomaskim/.rvm/rubies/ruby-1.9.3-p327/bin/ruby extconf.rb
checking for pg_config... no
No pg_config... trying anyway. If building fails, please try again with
--with-pg-config=/path/to/pg_config
checking for libpq-fe.h... no
Can't find the 'libpq-fe.h header
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.
Provided configuration options:
--with-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/Users/thomaskim/.rvm/rubies/ruby-1.9.3-p327/bin/ruby
--with-pg
--without-pg
--with-pg-dir
--without-pg-dir
--with-pg-include
--without-pg-include=${pg-dir}/include
--with-pg-lib
--without-pg-lib=${pg-dir}/lib
--with-pg-config
--without-pg-config
--with-pg_config
--without-pg_config
Gem files will remain installed in /Users/thomaskim/.bundler/tmp/1336/gems/pg-0.12.2 for inspection.
Results logged to /Users/thomaskim/.bundler/tmp/1336/gems/pg-0.12.2/ext/gem_make.out
An error occurred while installing pg (0.12.2), and Bundler cannot continue.
Make sure that `gem install pg -v '0.12.2'` succeeds before bundling.
It appears that you do not have postgres installed properly. I got a similar error when I was trying to install a pg module with npm. It disappeared after installing postgres properly. Here's a link to download: http://www.postgresql.org/download/macosx/