patch applied (cabal): Add test case for platform dependent and independent generated sources

[Duncan Coutts]

Tue May  1 07:27:16 PDT 2007  Duncan Coutts <duncan.coutts at worc.ox.ac.uk>
  * Add test case for platform dependent and independent generated sources
  The c2hs .hs files should go in dist/build while the happy .hs source
  should remain in the src dir and end up in the sdist tarball.

    A ./tests/preprocess/
    A ./tests/preprocess/preprocess.cabal
    A ./tests/preprocess/src/
    A ./tests/preprocess/src/C2HsExample.chs
    A ./tests/preprocess/src/HappyExample.y