anchor.diff:        maintainers = [ stdenv.lib.maintainers.eelco ];
         platforms = stdenv.lib.platforms.all;
       };
  +
  +    passthru = { inherit fromGit; };
  +  };
  +
  +  perl-bindings = { nix }: stdenv.mkDerivation {
  +    name = "nix-perl-" + nix.version;
  +
  +    inherit (nix) src;
  +
  +    postUnpack = "sourceRoot=$sourceRoot/perl";
  +
  +    nativeBuildInputs =
  +      [ perl pkgconfig curl nix libsodium ]
  +      ++ lib.optionals nix.fromGit [ autoreconfHook autoconf-archive ];
  +
  +    configureFlags =
  +      [ "--with-dbi=${perlPackages.DBI}/${perl.libPrefix}"
  +        "--with-dbd-sqlite=${perlPackages.DBDSQLite}/${perl.libPrefix}"
  +        "--with-www-curl=${perlPackages.WWWCurl}/${perl.libPrefix}"
  +      ];
     };
   
   in rec {
   
     nix = nixStable;
   
  -  nixStable = common rec {
  +  nixStable = (common rec {
       name = "nix-1.11.8";
       src = fetchurl {
         url = "http://nixos.org/releases/nix/${name}/${name}.tar.xz";
  
positive.code:       sha256 = "0mf7y7hvzw2x5dp482qy8774djr3vzcjaqq58cp82zdil8l7kwjd";
      };
      fromGit = true;
    });
  
  }
  
negative.code:         --replace 'std::less<Symbol>, gc_allocator<Value *>' \
                    'std::less<Symbol>, gc_allocator<std::pair<const Symbol, Value *> >'
      '';
    }) // { perl-bindings = nixStable; };
  
    nixUnstable = (lib.lowPrio (common rec {
      name = "nix-1.12${suffix}";
      suffix = "pre5152_915f62fa";
      src = fetchFromGitHub {
  