diff --git a/pkgs/development/compilers/ghc/head.nix b/pkgs/development/compilers/ghc/head.nix
index 8258ac27419..035ebc8b268 100644
--- a/pkgs/development/compilers/ghc/head.nix
+++ b/pkgs/development/compilers/ghc/head.nix
@@ -1,12 +1,12 @@
 { stdenv, fetchurl, ghc, perl, gmp, ncurses }:
 
 stdenv.mkDerivation rec {
-  version = "7.7.20130223";
+  version = "7.7";
   name = "ghc-${version}";
 
   src = fetchurl {
     url = "http://haskell.org/ghc/dist/current/dist/${name}-src.tar.bz2";
-    sha256 = "1naw6x1mjij10h9k4biard2pkzi6zml26vv4h34asprv0h6ymdbg";
+    sha256 = "1f4grj1lw25vb5drn4sn8fc1as3hwhk8dl659spi5fnbrs5k4wgb";
   };
 
   buildInputs = [ ghc perl gmp ncurses ];
@@ -19,6 +19,12 @@ stdenv.mkDerivation rec {
     DYNAMIC_BY_DEFAULT = NO
   '';
 
+  # The tarball errorneously contains an executable that doesn't work in
+  # Nix. Deleting it will cause the program to be re-built locally.
+  postUnpack = ''
+    rm -v $sourceRoot/libraries/integer-gmp/cbits/mkGmpDerivedConstants
+  '';
+
   preConfigure = ''
     echo "${buildMK}" > mk/build.mk
     sed -i -e 's|-isysroot /Developer/SDKs/MacOSX10.5.sdk||' configure