ruby19 +mactk on Mavericks broken

[craignied@…]

On Mavericks:

sudo port install ruby19 +mactk

The above installs fine.

Then, when trying to run a Ruby script, foot.rb as an example, with tk required/used:

/opt/local/lib/ruby1.9/1.9.1/rubygems/custom_require.rb:36:in `require': cannot load such file -- tk (LoadError)
    from /opt/local/lib/ruby1.9/1.9.1/rubygems/custom_require.rb:36:in `require'
    from /Users/craign/bin/foot.rb:6:in `<main>'