Rails 3.2 + OSX: Cannot install rmagick gem - ruby-on-rails

Question

I am trying to install an RoR app from Github and while running bundle install, I get this error:
Installing rmagick (2.13.1) with native extensions
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
/Users/adam/.rvm/rubies/ruby-1.9.3-p327/bin/ruby extconf.rb
checking for Ruby version >= 1.8.5... yes
extconf.rb:128: Use RbConfig instead of obsolete and deprecated Config.
checking for clang... yes
checking for Magick-config... yes
checking for ImageMagick version >= 6.4.9... yes
checking for HDRI disabled version of ImageMagick... yes
checking for stdint.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
--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/adam/.rvm/rubies/ruby-1.9.3-p327/bin/ruby
/Users/adam/.rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
from /Users/adam/.rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/mkmf.rb:506:in `try_cpp'
from /Users/adam/.rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/mkmf.rb:931:in `block in have_header'
from /Users/adam/.rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for'
from /Users/adam/.rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone'
from /Users/adam/.rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from /Users/adam/.rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone'
from /Users/adam/.rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from /Users/adam/.rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/mkmf.rb:280:in `postpone'
from /Users/adam/.rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for'
from /Users/adam/.rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/mkmf.rb:930:in `have_header'
from extconf.rb:193:in `<main>'
Gem files will remain installed in /Users/adam/.rvm/gems/ruby-1.9.3-p327/gems/rmagick-2.13.1 for inspection.
Results logged to /Users/adam/.rvm/gems/ruby-1.9.3-p327/gems/rmagick-2.13.1/ext/RMagick/gem_make.out
An error occurred while installing rmagick (2.13.1), and Bundler cannot continue.
Make sure that `gem install rmagick -v '2.13.1'` succeeds before bundling.
I've tried to run gem install rmagick -v '2.13.1', but I got the same error.
I am running on Mac OS X Lion. What am I missing?
Thank you in advance.

Answer 1

Try to run:
brew link imagemagick

Answer 2

Make sure you have a compiler. XCODE command line tools, or just install gcc.

Answer 3

I could not install the rmagick gem either...
To get Imagemagick installed correctly I first
brew remove libtool
brew install libtool --universal
Then I was able to install Imagemagick using this command:
brew install imagemagick --build-from-source
Then the rmagick gem installed correctly
The error message I was getting when rmagick would not install looked like:
linking shared-object RMagick2.bundle
ld: file not found: /usr/local/lib/libltdl.7.dylib for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [RMagick2.bundle] Error 1
make failed, exit code 2
This was for Imagemagick 6.8.9-8 and rmagick 2.13.2