On Wed, Mar 7, 2012 at 9:20 AM, Brandon Allbery
[...] The problem is not Lion, it is that
(a) Xcode 4.3 was only just released (b) Apple does not allow details of unreleased software to be discussed etc. before release which means (c) everyone who relies on Xcode got pretty much blindsided by all the changes.
ghc hasn't quite caught up with the changes yet. MacPorts is still struggling with some issues involved with the release; I don't know where Homebrew is with respect to it. Some of the other projects I'm involved with aren't Mac focused, and are just starting to realize that there are problems with Xcode 4.3 support.
If you need Haskell Platform working ASAP on OS X, remove Xcode 4.3, then download Xcode 4.2.1 from http://connect.apple.com/.
Thanks -- that sounds like a good approach. In the meantime I did find that building ghc and haskell-platform with Homebrew and the "--use-llvm" switch worked without errors, but I don't know enough about Haskell yet to tell if the result is useable. My long term goal is to install the Diagrams package, which needs GTK, Cairo etc. From what I've found so far that seems to be a serious undertaking too (although I'd be delighted to be corrected on that). Thanks, Stu