[Fedora-packaging] Ruby interpreter independence needs more work

[Toshio Kuratomi]

Since limited interpreter independence is a goal of the new guideline
(limited to rubygems), there needs to be more work done ironing out a few
details of that:

* It seems that the ruby(abi) Provides is only in ruby-libs; not in
  jruby{,-libs}. That means that an end user wanting to use jruby and having
  only rubygems installed still needs to have ruby-libs installed (because
  of the dep on ruby(abi).) Is this intentional?
* There needs to be more information about jruby and other alternate
  interpreters. In particular, the path macros for the jruby non-gem
  packages need to be added.
* I took a guess that non-gem packages should have separate
  subpackages for each interpreter since the thought is that rubygems can
  handle multiple interpreters but non-gem requires cannot. Further,
  I guessed that they should be named INTERPRETER-module, for instance,
  jruby-rpm.   The answer to whether jruby should Provide ruby(abi) is no,
  we also need to specify what non-gem packages for other packages should
  require (for instance, jruby(abi) = %{jruby_abi}).  If the answer is yes,
  we may still need to add new Requires for non-gem packages so that they
  are only associated with the correct interpreter (however, we might not
  need to have matching Provides... we might be able to just use package
  name for this)

-Toshio