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

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 * make xmonad recompile if any packages are modified.