As of lately, I've been using a bundled GHC app for OSX development. Makes it quite easy to keep (and switch between) multiple Haskell environments.
http://ghcformacosx.github.io/
Also, that app is great. Really nice that it comes with Cabal 1.20 .
IIRC, haskell.org used to point to a download of the Haskell Platform for OSX (definitely not to ghc.app at any rate), so when I saw that's where it pointed, I didn't even notice that they'd changed it.
As of lately, I've been using a bundled GHC app for OSX development. Makes it quite easy to keep (and switch between) multiple Haskell environments.
http://ghcformacosx.github.io/