title: Error trying to reinstall rugged gem
body: <p>I'm trying to reinstall rugged as it's causing issues with another program (Dandelion Deploy).</p>
  
  <p>I've recently updated my RVM and Ruby, and installed cmake and pkg-config again, but I get this error when I run the following command: <code>gem install rugged</code></p>
  
  <pre><code>Fetching: rugged-0.22.2.gem (100%)
  Building native extensions.  This could take a while...
  ERROR:  Error installing rugged:
      ERROR: Failed to build gem native extension.
  
      /Users/J/.rvm/rubies/ruby-2.0.0-p645/bin/ruby -r ./siteconf20150605-56781-qfplzm.rb extconf.rb
  checking for gmake... no
  checking for make... yes
  checking for cmake... yes
  checking for pkg-config... yes
   -- cmake .. -DBUILD_CLAR=OFF -DTHREADSAFE=ON -DBUILD_SHARED_LIBS=OFF -DCMAKE_C_FLAGS=-fPIC -DCMAKE_BUILD_TYPE=RelWithDebInfo -G "Unix Makefiles"
  *** 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/J/.rvm/rubies/ruby-2.0.0-p645/bin/ruby
      --use-system-libraries
  extconf.rb:13:in `sys': ERROR: 'cmake .. -DBUILD_CLAR=OFF -DTHREADSAFE=ON -DBUILD_SHARED_LIBS=OFF -DCMAKE_C_FLAGS=-fPIC -DCMAKE_BUILD_TYPE=RelWithDebInfo -G "Unix Makefiles"' failed (RuntimeError)
      from extconf.rb:66:in `block (2 levels) in &lt;main&gt;'
      from extconf.rb:65:in `chdir'
      from extconf.rb:65:in `block in &lt;main&gt;'
      from extconf.rb:62:in `chdir'
      from extconf.rb:62:in `&lt;main&gt;'
  
  extconf failed, exit code 1
  
  Gem files will remain installed in /Users/J/.rvm/rubies/ruby-2.0.0-p645/lib/ruby/gems/2.0.0/gems/rugged-0.22.2 for inspection.
  Results logged to /Users/J/.rvm/rubies/ruby-2.0.0-p645/lib/ruby/gems/2.0.0/extensions/x86_64-darwin-11/2.0.0/rugged-0.22.2/gem_make.out
  </code></pre>
  
  <p>I'm a frontender, so this is way out of my comfort zone. Any help appreciated!</p>
  
  <p>Mac OSX 10.7.5, Lion</p>