Spotted by the testsuite which I'm trying to resurrect.

Added an UnknownLicense String constructor so that we can remember
unknown license names and report them and prevent them from being
uploaded to hackage, but not fail hard with a parse error upon
encountering an unknown license. This does not add any new licesnes
or and new valid parses of existing licenses. The parsing phase
now allows an optional version like "GPL-3" however that would still
be classified as an unknown license at the moment. The point is it's
no longer a parse error but a semantic error instead.

Initially it's exactly the same format as Read/Show.
We can make it more liberal later.

The real difficulty with changing the license stuff is the parser in current
and older cabal versions is very fragile, it parses using Read so only
recognises those exact enum values and if parsing fails, then parsing the
whole .cabal file fails. We really need to make this more permissive for all
the enumerations so that we can make changes in future.

  add flags arguments to post-hooks, and have defaultUserHooks use postConf
  instead of preConf.

  changes to package description fields, as discussed on the libraries list:
  
  * allow both License and License-File, which now correspond to different
    fields of Package Description.
  
  * add Synopsis.
  
  * rename Hidden-Modules as Other-Modules.

- Rename Compat.* modules to Distribution.Compat.*
- Add {-# OPTIONS -cpp #-} to a few modules
- Distribution.Compat.ReadP: use real ReadP in GHC 6.3+
- new module: Distribution.Extension, contains Extension type
  formerly from Distribution.Misc.
- new module: Distribution.License, contains License type
  formerly from Distribution.Misc.
- remove Distribution.Misc
- new module: Distribution.ParseUtils, containing various parsing utilities
  formerly from Distribution.Package, that are re-used in 
  Distribution.InstalledPackageInfo.
- new module: Distribution.PackageDescription contains everything related
  to PackageDescription, which was formerly in Distribution.Package.
- Distribution.Package now contains only PackageId-related stuff.
- Distribution.InstalledPackageInfo: update for use in GHC, add
  parsing/pretty-printing.
- Compat.H98 is now Distribution.Compat.Error (it contained only stuff
  related to the Error monad, which isn't H98 anyway).
- remove imports of H98 libs (use hierarchical ones instead)
- configure now detects the GHC version (but doesn't do anything with it... yet)