darcs patch: added cppOptions and c2hsOptions

[Duncan Coutts]

On Fri, 2007-04-20 at 20:17 +1000, Duncan Coutts wrote:
> Hia Vivian,
[...]
> I'm looking into it.

I have a patch, I'll send it soonish (probably Monday) for other people
to review and test.

It's a general change to the way Cabal does pre-processing. Instead of
generating the .hs files in place in the source tree we put them all in
a special build tree in the dist dir (like where we put the .o and .hi
files, but not actually the same directory).

So the patch does that for all pre-processors, and in addition gives the
pre-processors a bit more information so that they can distinguish the
base name of the output file and the output dir prefix. This allows us
to tell c2hs this relative path so that it will use it when it generates
links to .h files in the .hs files it generates.

This also depends on a separate patch to c2hs.

Duncan