Because the system comes with them. Having two of these is just complicated.
They are both gems themselves, so gem that is already installed manages them.
Optional flag to install them anyway.
brewkit.rb changes ENV destructively, so lets not do that everytime a formula
is required. Now it's possible for other tools to require a formula
description without worrying about side-effects.
Ruby is not natively threaded; there is absolutely no reason to build against
pthread unless you intend to link against libraries themselves built with
pthread (tcl/tk). More information: http://blogs.sun.com/prashant/entry/ruby_and_enable_pthreads
As far as I can deduce, the source of that flag is in Dan Benjamin’s article,
here: http://hivelogic.com/articles/ruby-rails-leopard
However, he provides no explanation for its use, and did not respond to
commentors’ requests for said explanation; on top of that, I can find no useful
references anywhere else. Hence, removing it.
Old formulas are valid, but should be maintained in a separate branch if
that's what is needed.
The exact way we are going to do this is not yet agreed on.