anchor.diff:  
     nixFlakes = lib.lowPrio (callPackage common rec {
       name = "nix-2.4${suffix}";
  -    suffix = "pre20200521_00b562c";
  +    suffix = "pre20200622_334e26b";
   
       src = fetchFromGitHub {
         owner = "NixOS";
         repo = "nix";
  -      rev = "00b562c87ec4c3bbe514f5dc1f4d1c41f66f66bf";
  -      sha256 = "0s8is2czpkcj1x1kcjqgbnsbbl03w3fwjjiclsd44zh1ij3wb90s";
  -    };
  -
  -    crates = fetchurl {
  -      url = "https://hydra.nixos.org/build/118093786/download/1/nix-vendored-crates-2.4pre20200501_941f952.tar.xz";
  -      sha256 = "060f4n5srdbb8vsj0m14aqch7im79a4h5g3nrs41p1xc602vhcdl";
  +      rev = "334e26bfc2ce82912602e8a0f9f9c7e0fb5c3221";
  +      sha256 = "14a2yyn1ygymlci6hl5d308fs3p3m0mgcfs5dc8dn0s3lg5qvbmp";
       };
   
       inherit storeDir stateDir confDir boehmgc;
  
positive.code:             chmod u+w $out/lib/*.so.*
              patchelf --set-rpath $out/lib:${stdenv.cc.cc.lib}/lib $out/lib/libboost_thread.so.*
            ''}
          '' +
          # Unpack the Rust crates.
          lib.optionalString is24 ''
            tar xvf ${crates} -C nix-rust/
            mv nix-rust/nix-vendored-crates* nix-rust/vendor
          '' +
          # For Nix-2.3, patch around an issue where the Nix configure step pulls in the
          # build system's bash and other utilities when cross-compiling
  
negative.code: 
    nixUnstable = lib.lowPrio (callPackage common rec {
      name = "nix-2.4${suffix}";
      suffix = "pre7805_984e5213";
  
      src = fetchFromGitHub {
        owner = "NixOS";
        repo = "nix";
        rev = "984e521392b3f41f7cdab203e5c00f3e00e27a28";
        sha256 = "1dch48018dwzx9cysnfxrdpszav87s0d635zqw810mgmqpm25fw8";
      };
  
      inherit storeDir stateDir confDir boehmgc;
  