Test Cases for Configurations

[Neil Mitchell]

Hi Ian,

> That's not something that we want to be able to fix with configurations,
> though. We need to either implement all the functionality for all the
> implementations or to split the package up.

I disagree. I have a library which provides two modules, one for
compilers without multi-parameter type classes, and both for those
with them. I want this to be one library, but I want the modules
exported to vary based on the compiler being used. Since the library
is small, splitting it up would be a big pain.

Thanks

Neil