Since Truffle has a long ways to go before being widely useful, we've whitelisted the standard libraries we think are okay to load. These are implemented by way of stubs in lib/ruby/truffle/mri and they basically do a require_relative back to the standard lib file in JRuby. The problem is these stubs aren't currently being packaged so anyone using the tarballs as the source for their installation can't use even the whitelisted libs.

@mkristian -- Any help you can provide with packaging would be much appreciated.