anchor.diff:          cc           = {
             name    = "clang-9.9.9";
             cc      = "/usr";
  -          outPath = "${buildTools.tools}/Library/Developer/CommandLineTools/usr";
  +          outPath = nativePrefix;
           };
         };
       };
  
positive.code:       nativeTools  = false;
        nativeLibc   = true;
        binutils  = pkgs.darwin.cctools;
        cc        = pkgs.llvmPackages.clang;
        coreutils = pkgs.coreutils;
        shell     = "${pkgs.bash}/bin/bash";
        extraPackages = [ pkgs.libcxx ];
  
negative.code:       name = "stdenv-darwin-boot-1";
  
        inherit system config;
        inherit (stage0.stdenv) shell fetchurlBoot;
  
        initialPath = stage0.stdenv.initialPath ++ [ nativePrefix ];
  
        preHook = preHook + "\n" + ''
          export NIX_LDFLAGS_AFTER+=" -L/usr/lib"
  