patch applied (ghc): Use update-alternatives for handling generic tool names

[Neil Mitchell]

Hi

> > AIUI, the main reason for including cpphs with Hugs is that it is common
> > for a binary distribution of Hugs to be used on a platform (Windows)
> > with no C compiler available.
>
> Hmmm, I still fail to see why we should ship e.g. cpphs or hsc2hs with any
> Haskell implementation, but not Alex/Happy/Haddock/... What is so special
> about the former ones?

Even though some people may not like it, most Haskell programs use
CPP. Its got to the stage where Haskell compilers have a specific -cpp
flag, but not for any other programs. The community has chosen CPP to
be special.

> Let's keep things separate, even if this means that
> our source distros are a bit larger than they have to be if every tool was
> installed.

I think the Windows distribution of Hugs should include cpphs, just so
its feasible to install packages with Cabal - otherwise all of them
are likely to fail. License issues aren't a problem on Windows because
no one cares :-)

Thanks

Neil