diff --git a/pkgs/development/compilers/ghc/6.12.1.nix b/pkgs/development/compilers/ghc/6.12.1.nix
index 9b108fbad8a..0360db24954 100644
--- a/pkgs/development/compilers/ghc/6.12.1.nix
+++ b/pkgs/development/compilers/ghc/6.12.1.nix
@@ -1,15 +1,15 @@
 {stdenv, fetchurl, ghc, perl, gmp, ncurses}:
 
 stdenv.mkDerivation rec {
-  version = "6.12.0.20091010";
+  version = "6.12.1";
   
   name = "ghc-${version}";
   
   homepage = "http://haskell.org/ghc";
 
   src = fetchurl {
-    url = "http://darcs.haskell.org/~ghc/dist/6.12.1rc1/${name}-src.tar.bz2";
-    sha256 = "903552917778329fc79cc273ece81030324006f47157ddd4278cb08c1c637fd3";
+    url = http://haskell.org/ghc/dist/6.12.1/ghc-6.12.1-src.tar.bz2;
+    sha256 = "0ajm4sypk4zgjp0m6i03fadyv5dm9vlqfnvsx1g94yk7vnd9zyfd";
   };
 
   buildInputs = [ghc perl gmp ncurses];
@@ -34,6 +34,8 @@ stdenv.mkDerivation rec {
   meta = {
     inherit homepage;
     description = "The Glasgow Haskell Compiler";
+    maintainers = [stdenv.lib.maintainers.marcweber];
+    platforms = stdenv.platforms.linux;
   };
 
 
diff --git a/pkgs/development/libraries/haskell/cabal/cabal.nix b/pkgs/development/libraries/haskell/cabal/cabal.nix
index c4ea86a4ac7..5c83e90dc44 100644
--- a/pkgs/development/libraries/haskell/cabal/cabal.nix
+++ b/pkgs/development/libraries/haskell/cabal/cabal.nix
@@ -37,7 +37,7 @@ attrs :
             propagatedBuildInputs = [];
 
             # library directories that have to be added to the Cabal files
-            extraLibDirs = attrs.lib.lists.concatMap (x : [ (x + "/lib64") (x + "/lib") ]) self.propagatedBuildInputs;
+            extraLibDirs = [];
 
             # compiles Setup and configures
             configurePhase = ''
@@ -46,7 +46,16 @@ attrs :
               for i in Setup.hs Setup.lhs; do
                 test -f $i && ghc --make $i
               done
-              ./Setup configure --verbose --prefix="$out" ${toString (map (x : "--extra-lib-dir=" + x) self.extraLibDirs)} $configureFlags
+
+              for p in $propagatedBuildInputs; do
+                for d in lib{,64}; do
+                  if [ -e "$p/$d" ]; then
+                    extraLibDirs="$extraLibDirs --extra-lib-dir=$p/$d"
+                  fi
+                done
+              done
+
+              ./Setup configure --verbose --prefix="$out" $extraLibDirs $configureFlags
 
               eval "$postConfigure"
             '';
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index c7ebf381dcb..57348193e91 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -1921,7 +1921,7 @@ let
   # For several compiler versions, we export a large set of Haskell-related
   # packages.
 
-  haskellPackages = haskellPackages_ghc6104;
+  haskellPackages = haskellPackages_ghc6121;
 
   /*
   haskellPackages_ghc642 = import ./haskell-packages.nix {