Example to go with the Ruby Magic blog post.
To hack on this run:
$ bin/setup
$ rake compile
`$ bin/console
irb(main):001:0> CFromRubyExample::Helpers.string("a string")
=> "String from Ruby: 'a string'"
irb(main):002:0> CFromRubyExample::NativeHelpers.string("a string")
=> "String from C: 'a string'"
irb(main):003:0>