patch applied (cabal): Make checking program versions not produce error spew

[Duncan Coutts]

Thu Aug 30 07:43:12 PDT 2007  Duncan Coutts <duncan at haskell.org>
  * Make checking program versions not produce error spew
  Redirect stderr to /dev/null (or NUL on windows) and throw an exception
  like rawSystemExit does rather than calling die which prints an unhelpful
  message before throwing an exception. It's not an overall failure to not
  be able to establish the version of a program, since we check later if we
  actually have any requirement for any particular version anyway.
  So for example this makes running configure with an old version of c2hs
  that doesn't grok --numeric-version not produce unhelpful output that
  make people think that configure failed.

    M ./Distribution/Simple/Utils.hs -15 +16