JRuby/lib/ruby/shared/pty.rb call to forkpty doesnt work on Windows

[headius]

From http://jira.codehaus.org/browse/JRUBY-7198

FFI::NotFoundError: Function 'forkpty' not found in [msvcrt.dll]
The fix is to change 'forkpty' to '_popen' in pty.rb
But then you get the same problem with function 'close' and 'execv' and presumably several others.
This was accessed by having the zeus gem in Gemfile, and having run the bundle, then running: bundle exec rspec spec/lib