What about distributing debugger-X.Y.Z-java and friends using jruby-debug?
Since I'm not that familiar with jruby or use it much, I"m leaving this for anyone interested or with the proper skills. Open to any pull requests that want to merge/use jruby-debug from debugger.
It looks like some work is already done here: https://github.com/ruby-debug/ruby-debug. It seems to support both java and C extensions depending on the RUBY_ENGINE, so if someone is interesed in this, that could be an starting point.