patch applied (cabal): Actually -stubdir only works well in ghc-6.8 due to -I search dir mess

[Duncan Coutts]

Wed Sep 26 06:18:43 PDT 2007  Duncan Coutts <duncan at haskell.org>
  * Actually -stubdir only works well in ghc-6.8 due to -I search dir mess
  In ghc-6.6 the Foo/Bar.hc files only #include "Bar_stub.h" rather than
  #include "Foo/Bar_stub.h". This means when we set the stubdir so that the
  _stub.h files don't sit next to the .hs file then the include search path
  is not right to find the _stub.h file. In ghc-6.8 this is fixed so that
  it adds the -stubdir path to the include search path when calling gcc.

    M ./Distribution/Simple/GHC.hs -1 +1