patch applied (cabal): Find original sources for main-is when creating sdist

[Duncan Coutts]

Thu Jan 31 03:49:09 PST 2008  Duncan Coutts <duncan at haskell.org>
  * Find original sources for main-is when creating sdist
  Also add a package sanity check that main-is must specify a .hs or .lhs file.
  So the bahaviour is now that main-is specifies the main source file, even if
  that is generated by a pre-processor. This isn't really a change in behaviour
  since previously if you specified main-is: main.hsc then it would try to
  pass the .hsc file to ghc dirctly which would not work. For ticket #14 things
  were fixed to that it would look for main.hsc if you used main-is: main.hs an
  that file did not exist directy. This completes the other half, of actually
  being able to make a src distribution. So this should fix bug #217.
  Note that this still needs some work, we do not run platform-independent
  preprocessors and put the result into the tarball for main-is files.
  Generally, main-is has been the second class citizen compared to normal
  modules. We should try and refactor so both use the same code paths.

    M ./Distribution/PackageDescription.hs -4 +8
    M ./Distribution/Simple/SrcDist.hs -1 +5