ghc and the hs-packages now simply include the necessary (haskell)
package description files in lib/ghc/package.conf.d and update the
package.cache by running ghc-pkg recache at the end. register and
unregister scripts are no longer needed.
and the line with the unregister.sh script down to the bottom of
the plist. Silences all the blurb about ".../*.haddock doesn't exist
or isn't a file."