[jhc] compiling JHC against syb-0.2

[Ben Millwood]

Hi,

Since version 0.2, Data.Generics has re-exported the module
Data.Generics.Builders which in turn exports empty :: (Data a) => a

src/Info/Info.hs imports Data.Generics and defines empty :: Info

As a result I can't compile JHC using syb 0.2. It seems like the
Data.Generics import in src/Info/Info.hs isn't necessary to build on
my system, so it can be just removed.

But then you get the same conflict in src/FrontEnd/KindInfer.hs, this
time with Doc.DocLike.empty, and if that's fixed, again in
src/FrontEnd/Class.hs. Explicitly specifying the entities imported in
both cases allows the compile to finish.

Tested on the darcs version, and I can provide a patch if necessary,
though I'm not terribly familiar with darcs.

My apologies if this is already well-known :) I had a poke through
recent archives and the issue tracker, didn't see anything
particularly obvious.