>> Why does GHC still think the package is hidden?
> You need to add "directory" to the Build-Depends instruction in the cabal file

Thanks Olivier. Haddock now builds with this list for 'build-depends':

base>=1.0, haskell98>=1.0, directory>=1.0, process>=1.0, containers>=0.1, array>=0.1, pretty>=1.0

The 'build' step also requires Happy and Alex to be installed, which are not mentioned in the cabal file.

Thanks,
Greg