Major Haskell packages overhaul.

Several changes, some highlights:

  * Structure of haskell-packages.nix updated. It's now easier to
    select different default versions of packages for different
    versions of GHC.

  * GHC 7.0.2 is now default.

  * Haskell Platform 2011.2.0.0 has been added and is now default.

  * Several packages have been updated
    (gtk2hs, gitit, xmonad, darcs, ...).

  * Some old packages have been removed.

svn path=/nixpkgs/trunk/; revision=26288

pkgs/development/tools/parsing/alex/2.3.5.nix

@@ -0,0 +1,12 @@
+{cabal, perl}:
+
+cabal.mkDerivation (self : {
+  pname = "alex";
+  version = "2.3.5"; # Haskell Platform 2011.2.0.0
+  name = self.fname;
+  sha256 = "0lyjiq4lmii2syk6838ln32qvn8c0ljf1ypsggahy748k05x79if";
+  extraBuildInputs = [perl];
+  meta = {
+    description = "A lexical analyser generator for Haskell";
+  };
+})

pkgs/development/tools/parsing/happy/1.18.6.nix

@@ -0,0 +1,13 @@
+{cabal, mtl, perl}:
+
+cabal.mkDerivation (self : {
+  pname = "happy";
+  version = "1.18.6"; # Haskell Platform 2011.2.0.0
+  name = self.fname;
+  sha256 = "0q6dnwihi1q761qdq0hhi733nh5d53xz6frwmr7slpvrp6v8y344";
+  extraBuildInputs = [perl];
+  propagatedBuildInputs = [mtl];
+  meta = {
+    description = "Happy is a parser generator for Haskell";
+  };
+})

pkgs/development/tools/parsing/happy/happy-1.17.nix

@@ -1,12 +0,0 @@
-{cabal, perl}:
-
-cabal.mkDerivation (self : {
-
-  # requires cabal-1.2 (and therefore, in Nix, currently ghc-6.8)
-
-  pname = "happy";
-  version = "1.17";
-  name = self.fname;
-  sha256 = "dca4e47d17e5d538335496236b3d2c3cbff644cf7380c987a4714e7784c70a2b";
-  extraBuildInputs = [perl];
-})