mxcl/homebrew — pull request #23724 by markcornick (2013-10-29 01:45:12+00:00)
Title: ruby-build: recommended depends on openssl and libyaml

ruby-build can use these, if installed, instead of downloading and
installing its own copies of these libraries every time a Ruby
interpreter that needs them is installed.

Since the most recent MRI needs openssl and the most recent RBX needs
libyaml, this makes sense as :recommended to me, but could also be
:optional if that makes more sense to you.