Error installing pg gem on osx

Question

I am on osx 10.6.7 trying to run bundle install on a new rails 3.0.7 app and it keeps failing when trying to build the pg gem. It keeps telling me that I have need the developer tools. But as far as I can tell I have the developer tools installed.

Here is the output of xcodebuild -version

Xcode 3.2.6
Component versions: DevToolsCore-1809.0; DevToolsSupport-1806.0
BuildVersion: 10M2518

Here is the output of the failed pg gem build

/Users/bm/.rvm/rubies/ruby-1.9.2-head/bin/ruby extconf.rb --with-pg-config=/Library/PostgreSQL/8.4/bin/pg_config
Using config values from /Library/PostgreSQL/8.4/bin/pg_config
checking for libpq-fe.h... *** 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
    --without-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/bm/.rvm/rubies/ruby-1.9.2-head/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
/Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/mkmf.rb:368:in `try_do': The complier failed to generate an executable file. (RuntimeError)
You have to install development tools first.
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/mkmf.rb:452:in `try_cpp'
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/mkmf.rb:853:in `block in find_header'
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/mkmf.rb:693:in `block in checking_for'
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/mkmf.rb:280:in `block (2 levels) in postpone'
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/mkmf.rb:254:in `open'
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/mkmf.rb:280:in `block in postpone'
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/mkmf.rb:254:in `open'
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/mkmf.rb:276:in `postpone'
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/mkmf.rb:692:in `checking_for'
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/mkmf.rb:852:in `find_header'
    from extconf.rb:31:in `<main>'


Gem files will remain installed in /Users/bm/.rvm/gems/ruby-1.9.2-head@rc_search/gems/pg-0.11.0 for inspection.
Results logged to /Users/bm/.rvm/gems/ruby-1.9.2-head@rc_search/gems/pg-0.11.0/ext/gem_make.out
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/rubygems/installer.rb:486:in `block in build_extensions'
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/rubygems/installer.rb:446:in `each'
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/rubygems/installer.rb:446:in `build_extensions'
    from /Users/bm/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/rubygems/installer.rb:198:in `install'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/gems/bundler-1.0.0/lib/bundler/source.rb:100:in `install'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/gems/bundler-1.0.0/lib/bundler/installer.rb:55:in `block in run'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/gems/bundler-1.0.0/lib/bundler/spec_set.rb:12:in `block in each'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/gems/bundler-1.0.0/lib/bundler/spec_set.rb:12:in `each'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/gems/bundler-1.0.0/lib/bundler/spec_set.rb:12:in `each'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/gems/bundler-1.0.0/lib/bundler/installer.rb:44:in `run'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/gems/bundler-1.0.0/lib/bundler/installer.rb:8:in `install'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/gems/bundler-1.0.0/lib/bundler/cli.rb:217:in `install'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/gems/bundler-1.0.0/lib/bundler/vendor/thor/task.rb:22:in `run'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/gems/bundler-1.0.0/lib/bundler/vendor/thor/invocation.rb:118:in `invoke_task'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/gems/bundler-1.0.0/lib/bundler/vendor/thor.rb:246:in `dispatch'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/gems/bundler-1.0.0/lib/bundler/vendor/thor/base.rb:389:in `start'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/gems/bundler-1.0.0/bin/bundle:13:in `<top (required)>'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/bin/bundle:19:in `load'
    from /Users/bm/.rvm/gems/ruby-1.9.2-head@global/bin/bundle:19:in `<main>'

Any help would be immensely appreciated. FYI I also tried building the app with a mysql and essentially got the same stack. So I'm pretty sure I'm missing some sort of developer build tools, but I just don't know which ones. :(

Answer 1

What worked for me was Zag Zag's comment:

~/projects/foo$ env ARCHFLAGS="-arch x86_64" gem install pg
Building native extensions.  This could take a while...
Successfully installed pg-0.11.0
1 gem installed
Building YARD (yri) index for pg-0.11.0...

~/projects/foo$ bundle 
...
Using pg (0.11.0) 
...
Your bundle is complete! Use `bundle show [gemname]` to see where a bundled gem is installed.

Answer 2

If you are using the PostgreSQL app on osx, you may need to change path the following (as the location of the binaries and config files changes) instead of the path shown in lesyk's answer:

export PATH=/Applications/Postgres.app/Contents/MacOS/bin:${PATH}