title: Failed to build gem native extension when Installing capybara-webkit (0.12.1)
body: <p>I can't install the <a href="https://github.com/thoughtbot/capybara-webkit" rel="nofollow">Capybara Webkit Driver</a> as I receive this error: </p>
  
  <pre><code>Installing capybara-webkit (0.12.1) with native extensions
  Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
  
          c:/RailsInstaller/Ruby1.9.3/bin/ruby.exe extconf.rb 
  </code></pre>
  
  <p>I'm running on Windows 7 x64 and as you can see, installed with the RailsInstaller for Windows. I tried <code>gem install capybara-webkit</code> and right now I have it in my gem file but both return the same error.</p>
  
  <p>Anyone know how to solve this issue?</p>