Current version of rubygems does not run without this (though they will be making a small workaround for us for the time being). Might as well audit some other keys in here since we seem to be missing lots of keys. The specific one causing problems is:
We do supply vendordir when it is configured via a flag or property. That was requested by some Linux package maintainers. But I'm not sure if we have to provide it. It would seem especially strange to provide it when we don't put it in LOAD_PATH, which is exactly why it's configurable.