Install Cucumber on Mac

Problem

Fail to install Cucumber

% sudo gem install cucumber
Building native extensions.  This could take a while...
ERROR:  Error installing cucumber:
	ERROR: Failed to build gem native extension.

        /Users/XXXX/.rbenv/versions/1.9.3-p194/bin/ruby extconf.rb
checking for main() in -lc... *** 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.

Solution

Install gcc

1. Download Xcode from App Store
2. Xcode -> Preferences -> Downloads -> Command Line Tools