[xmonad] darcs patch: make xmonad recompile if any packages are modified.

[Don Stewart]

droundy:
> WARNING:  I haven't actually tested this patch.  But it ought to work as
> advertized, and should give a good start to someone interested in making
> this work (right now, I don't want to wait half an hour for xmonad-contrib
> to recompile in order to test it).  Perhaps the cabal folks could also make
> use of this idea (checking timestamps), so xmonad could segfault less
> often.  Or we could jury-rig this check into Setup.lhs ourselves...
> 
> David
> 
> Wed Mar 19 09:37:38 PDT 2008  David Roundy <droundy at darcs.net>
>   * make xmonad recompile if any packages are modified.

I'm not going to apply this, but we can use it as more leverage on
ticket:

    http://hackage.haskell.org/trac/ghc/ticket/1372

See the faq for this issue:

    http://haskell.org/haskellwiki/Xmonad/Frequently_asked_questions#Help.21_xmonad_just_segfaulted

Things have been improving in this area, but there's still a couple
of scenarios that cause problems:

    * packages changing their ABI
    * source changes in a partially compile directory

If either of these happen cabal should require a recompile.

-- Don