anchor.diff:  {stdenv, fetchurl, which, file, perl, curl, python27, makeWrapper}:
   
  -let snapshotName = "rust-stage0-2014-01-05-a6d3e57-linux-x86_64-aa8fbbacdb1d8a078f3a3fe3478dcbc506bd4090.tar.bz2"; in
  +with if stdenv.system == "i686-linux" then {
  +  platform = "linux-i386";
  +  snapshot = "03e60be1f1b90dddd15f3597bc45ec8d9626b35d";
  +  snapshot_sha = "1v1l082gj7d2d4p53xgsxz2k965jcgqhw4cyxmjxc6yh5fw0idx6";
  +  target = "i386-unknown-linux-gnu";
  +} else if stdenv.system == "x86_64-linux" then {
  +  platform = "linux-x86_64";
  +  snapshot = "aa8fbbacdb1d8a078f3a3fe3478dcbc506bd4090";
  +  snapshot_sha = "17inc23jpznqp0vnskvznm74mm24c1nffhz2bkadhvp2ww0vpjjx";
  +  target = "x86_64-unknown-linux-gnu";
  +} else if stdenv.system == "x86_64-darwin" then {
  +  platform = "macos-x86_64";
  +  snapshot = "ec746585cb20d1f9edffec74f6ff8be6e93a75f7";
  +  snapshot_sha = "0r8f8x3x8jb1hm40pbgj4i9ll2y5dgjgvj24qg7mp4crbqcqhkd2";
  +} else {};
  +let snapshotDate = "2014-01-05";
  +    snapshotRev = "a6d3e57";
  +    snapshotName = "rust-stage0-${snapshotDate}-${snapshotRev}-${platform}-${snapshot}.tar.bz2"; in
   stdenv.mkDerivation {
     name = "rust-0.9";
   
  
positive.code: 
    # Modify the snapshot compiler so that is can be executed
    preBuild = if stdenv.isLinux then ''
      make x86_64-unknown-linux-gnu/stage0/bin/rustc
      patchelf --interpreter ${stdenv.glibc}/lib/ld-linux-x86-64.so.2 \
               --set-rpath ${stdenv.gcc.gcc}/lib/ \
               x86_64-unknown-linux-gnu/stage0/bin/rustc
    '' else null;
  
    # rustc requires cc
  
negative.code:   # We need rust to build rust. If we don't provide it, configure will try to download it
    snapshot = fetchurl {
      url = "http://static.rust-lang.org/stage0-snapshots/${snapshotName}";
      sha256 = snapshot_sha;
    };
  
    # Put the snapshot where it is expected
  