anchor.diff:  
   */
   
  -with ((import ./common.nix) {inherit stdenv; version = "0.13.0-pre-2763-g6366631";});
  +with ((import ./common.nix) {inherit stdenv; version = "0.13.0-pre-3497-g6539cb4";});
   
   let snapshot = if stdenv.system == "i686-linux"
  -      then "3daf531aed03f5769402f2fef852377e2838db98"
  +      then "b880b98d832c9a049b8ef6a50df50061e363de5a"
         else if stdenv.system == "x86_64-linux"
  -      then "4f3c8b092dd4fe159d6f25a217cf62e0e899b365"
  +      then "82a09c162474b69d2d1e4e8399086f3f0f4e31c3"
         else if stdenv.system == "i686-darwin"
  -      then "2a3e647b9c400505bd49cfe56091e866c83574ca"
  +      then "569055bb10d96ab25f78ecf2c80ffbccd5e69b8d"
         else if stdenv.system == "x86_64-darwin"
  -      then "5e730efc34d79a33f464a87686c10eace0760a2e"
  +      then "cff1f9ebd63dae6890359b7d353bd9486d8ecdfc"
         else abort "no-snapshot for platform ${stdenv.system}";
  -    snapshotDate = "2014-12-20";
  -    snapshotRev = "8443b09";
  +    snapshotDate = "2015-01-04";
  +    snapshotRev = "b2085d9";
       snapshotName = "rust-stage0-${snapshotDate}-${snapshotRev}-${platform}-${snapshot}.tar.bz2";
   
   in stdenv.mkDerivation {
  
positive.code: 
    src = fetchgit {
      url = https://github.com/rust-lang/rust;
      rev = "63666317214788329e0b7680929b09823f127d83";
      sha256 = "1saf6ycy5dzp1bxypzqisi4g4p0y1czbgr82xbrw5c81x5c274zk";
    };
  
    # We need rust to build rust. If we don't provide it, configure will try to download it.
  
negative.code: 
      substituteInPlace src/rust-installer/gen-install-script.sh \
        --replace /bin/echo "${coreutils}/bin/echo"
      substituteInPlace src/rust-installer/gen-installer.sh \
        --replace /bin/echo "${coreutils}/bin/echo"
    '';
  
    buildInputs = [ which file perl curl python27 makeWrapper git valgrind procps ];
  