I'm going to collect some notes here on this page to talk about things that we need to change in the Ruby standard libraries and/or Rails to make it compatible with IronRuby.
This file contains references to the Win32API library. Since we don't support this library under IronRuby, we need to introduce a new code path. I'm changing it here, and will likely add the changed file to the IronRuby libs directory to put it ahead of where the existing tmpdir.rb shows up on the libraries search path.