haskell-gtk still fails an assertion on Darwin; my attempt to fix that

hasn't worked, so I revert the change. Someone with access to that
platform will have to worry about those on Hydra assertions, I'm afraid.

svn path=/nixpkgs/trunk/; revision=29143

pkgs/top-level/haskell-packages.nix

@@ -616,7 +616,6 @@ let result = let callPackage = x : y : modifyPrio (newScope result.final x y);
 
   gtk = callPackage ../development/libraries/haskell/gtk {
     inherit (pkgs.gtkLibs) gtk;
-    glibc = if pkgs.stdenv.isLinux then pkgs.stdenv.glibc else null;
   };
 
   gtk2hsBuildtools = callPackage ../development/libraries/haskell/gtk2hs-buildtools {};