When I run 

```
 abhay$ gem install capybara-webkit

```

I get the following error messages.

```
 Building native extensions.  This could take a while...
 ERROR:  Error installing capybara-webkit:
ERROR: Failed to build gem native extension.

    /Users/abhay/.rvm/rubies/ruby-1.9.2-p180/bin/ruby extconf.rb

  Gem files will remain installed in /Users/abhay/.rvm/gems/ruby-1.9.2-p180/gems/capybara-     webkit-0.12.1 for inspection.
  Results logged to /Users/abhay/.rvm/gems/ruby-1.9.2-p180/gems/capybara-webkit-0.12.1/./gem_make.out

```