Mac OS X, Gem Install Problem: "ERROR: Failed to build gem native extension"

If you are getting this error:

ERROR: Failed to build gem native extension.

when installing a ruby gem on OSX, then chances are you do not have the tools necessary to execute 'make' as part of the install process. Its an easy fix...install the XCode which will also install the necessary tools for the 'make' process. You can do this by either:

1. Downloading from the AppStore, or from the Developer Centre
2. Mac Xcode Tools off the Mac OS X Install Disc 1

That fixed it for me anyway. Enjoy!