If you just want to use 1.9.3 p0 with ruby-debug on RVM, here’s one I prepared earlier (thanks to @ed_ruder):

$ curl https://github.com/sj26/ruby-1.9.3-p0/compare/ruby_1_9_3_0...master.diff > /tmp/ruby-1.9.3-visibility.diff
$ rvm install 1.9.3-p0 --patch /tmp/ruby-1.9.3-visibility.diff
$ rvm use 1.9.3-p0
$ gem install ruby-debug19

The full explanation is in my previous post.