Patch for Cabal

[Dominic Steinitz]

Hi Duncan,

I finally finished off the patch for https://github.com/haskell/cabal/issues/1460 I was working on with your help at ZuriHac.

It's in my fork of cabal here: https://github.com/idontgetoutmuch/cabal/commit/f76ab8b6c0945b82746d664918ebf6623d75d108

I am not sure what to do next. How should we test it? We need to make sure it doesn't break anything and also that it actually fixes the problem.

Curses! I just forgot I don't check which version of cabal is being used so that we pass the old style --constraint rather than the new style --dependency for old cabals.

Before I fix that, perhaps you wouldn't mind thinking about testing and also have a look at the code to make sure I haven't done something stupid.

Dominic Steinitz
dominic at steinitz.org
http://idontgetoutmuch.wordpress.com