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

[Sven Panne]

On Friday 16 March 2007 15:45, Ian Lynagh wrote:
> The only issue I see is that Cabal calls hsc2hs when necessary, but alex
> and happy are already in the that situation. Unfortunately packages
> can't depend on tools, they just fail when asked to build. Perhaps there
> should be a cabal "Tools:" field similar to "Extensions:"?

I think that we are crossing a boundary here where Cabal is no longer in 
charge: Alex, Happy, hsc2hs etc. are all tools, which are *accidentally* 
implemented in Haskell, but there is no deep reason why they have to be. 
Resolving dependencies outside the Haskell world is the task of tools like 
YaST, yum, etc.  I imagine that users of those native package systems will 
often use Cabal only indirectly when they install a Haskell package via YaST 
and friends. Having a "Tools:" field will ease the automatic generation 
of .spec files from .cabal files, I guess.

Cheers,
   S.