From: Tom M <thomas.macklin@...>
Date: 2007-09-07T22:40:08+09:00
Subject: Re: building an extension gem and including a library source

Are you using the Gem::Specifications#extesions method? in your
gemspec?  This builds the extension when you install the gem
automatically.  You just say

spec.extensions = ["ext/[whatever]/extconf.rb"]

in your gemspec