tex_list, Rails 2.3.10, etc.
Use Bundler to manage Erubis and Rubyzip. (Remove the vendored versions.)
Remove the vendored sqlite3-ruby. Instead, add support for Bundler (which is vendored). Before running the new Instiki, do a ruby bundle which will install all of the needed gems locally. (If you need to, tweak the contents of Gemfile.)