anchor.diff:      };
   
       inherit storeDir stateDir confDir boehmgc;
  -
  +  } // stdenv.lib.optionalAttrs stdenv.cc.isClang {
       stdenv = llvmPackages_6.stdenv;
  -  };
  +  });
   
     nixUnstable = lib.lowPrio (callPackage common rec {
       name = "nix-2.3${suffix}";
  
positive.code: , stateDir ? "/nix/var"
  , confDir ? "/etc"
  , boehmgc
  , llvmPackages_6
  }:
  
  let
  
negative.code:     inherit storeDir stateDir confDir boehmgc;
    };
  
    nixStable = callPackage common (rec {
      name = "nix-2.2.2";
      src = fetchurl {
        url = "http://nixos.org/releases/nix/${name}/${name}.tar.xz";
  