Specific license field

[Neil Mitchell]

Hi

> We're not trying to nail down every last nuance in the licenses (e.g. I
> don't think we need to be trying to distinguish GPL-2 from GPL-2+).

So how is a Cabal library author meant to explain their intent? I just
want to go with whatever helps the distros package my tools (although
I don't want to put explicit licensing in each source code file), and
it's the distros who have been asking for clarification.

Knowing that GPL-2 is coming is great, but if it's newer Cabal/GHC
only I'll just leave it as a comment in the .cabal file, then move it
over in a few years time.

Thanks, Neil