@k0kubun Maybe I'm wrong, but I think using require 'erb.so' may make it more difficult for JRuby to provide a compatible extension. Ideally, I think it would be best to require 'erb/html_escape' or something similar to make it easier for alternative ruby implementations. CC @headius to confirm that this would make things easier for JRuby.
I'd like to get the final name for the extension decided before I start using it in Roda and Erubi.