patch applied (cabal): Add improved xargs style function

[Duncan Coutts]

Sun Jun  7 11:02:14 PDT 2009  Duncan Coutts <duncan at haskell.org>
  * Add improved xargs style function
  More flexible and based on the ProgramInvocation stuff

    M ./Distribution/Simple/Program/Run.hs -2 +78

View patch online:
http://darcs.haskell.org/cabal/_darcs/patches/20090607180214-adfee-1dfa2fd447b948ec0b9d524efc852e5f8f666764.gz