Meet the DevKit
Sometimes you just want RubyGems to build that cool native, C-based extension without squawking. Who’s your buddy? The DevKit that’s who!
The RubyInstaller Development Kit is a toolkit that makes it easy to build and use native C/C++ extensions such as RDiscount and RedCloth for Ruby on Windows.
Simply download, double-click, choose an installation directory, run the Ruby install helper script and you’re ready to start using native Ruby extensions. For installation details check out the Development Kit wiki page.