Rubinius bug fixes

[josh]

1. Unset RUBYLIB for Rubinius otherwise it aborts with this error:

   ERROR: Please unset RUBYLIB to configure Rubinius

2. Remove conflicting aliases for "ruby", "irb", "rake", etc. I believe this was a regression introduced in 995b1c4.

[MikeMcQuaid]

We generally don't try to fix users' environments for them. If Rubinius prints that, it's enough for me. Can you explain 2) a bit more please?

[josh]

Homebrew takes a number of to setup a clean build environment to avoid build issues on peoples system. A good example is wiping CDPATH which interferes without alot of makefiles. https://github.com/mxcl/homebrew/blob/master/Library/Homebrew/extend/ENV.rb#L6-7

Whats annoying is that rubinius' setup just aborts if you have RUBYLIB set in your env. https://github.com/evanphx/rubinius/blob/master/Rakefile#L4-7

I understand not wanting to cover edge ENV variables but this is very specific to the rubinius build process.

An ideal solution would be spawning a clean subshell for all formula to build in. This is a bit more work though.

[MikeMcQuaid]

I might fix the second but I won't change the first at the moment, can you please explain the second?

[josh]

Prior to 995b1c4, binaries for ruby, gem, irb, etc were not linked in. Now they are clobbering my main ruby binary installed via the main ruby formula. We should remove them or namespace as done in the jruby formula. Namespacing seems silly when you can already access rubinius irb with rbx -S irb.

[MikeMcQuaid]

Ok, thanks. Pulled the second. Please open an issue and/or another pull request about the first.

[josh]

Follow up ticket #3715