anchor.diff:        sha256 = "0mf7y7hvzw2x5dp482qy8774djr3vzcjaqq58cp82zdil8l7kwjd";
       };
       fromGit = true;
  -  });
  +  })) // { perl-bindings = perl-bindings { nix = nixUnstable; }; };
   
   }
  
positive.code:         --replace 'std::less<Symbol>, gc_allocator<Value *>' \
                    'std::less<Symbol>, gc_allocator<std::pair<const Symbol, Value *> >'
      '';
    };
  
    nixUnstable = lib.lowPrio (common rec {
      name = "nix-1.12${suffix}";
      suffix = "pre5152_915f62fa";
      src = fetchFromGitHub {
  
negative.code:       [ "--with-store-dir=${storeDir}"
          "--localstatedir=${stateDir}"
          "--sysconfdir=/etc"
          "--disable-init-state"
          "--enable-gc"
        ]
        ++ lib.optionals (!lib.versionAtLeast version "1.12pre") [
          "--with-dbi=${perlPackages.DBI}/${perl.libPrefix}"
          "--with-dbd-sqlite=${perlPackages.DBDSQLite}/${perl.libPrefix}"
          "--with-www-curl=${perlPackages.WWWCurl}/${perl.libPrefix}"
        ];
  
  