anchor.diff:        inherit
           gnumake gzip gnused bzip2 gawk ed xz patch bash python3
           ncurses libffi zlib gmp pcre gnugrep
  -        coreutils findutils diffutils patchutils ninja;
  +        coreutils findutils diffutils patchutils ninja libxml2;
   
         # Hack to make sure we don't link ncurses in bootstrap tools. The proper
         # solution is to avoid passing -L/nix-store/...-bootstrap-tools/lib,
  
positive.code:       gnugrep llvmPackages.clang-unwrapped llvmPackages.clang-unwrapped.lib patch pcre.out gettext
        binutils.bintools darwin.binutils darwin.binutils.bintools
        curl.out openssl.out libssh2.out nghttp2.lib libkrb5
        cc.expand-response-params
      ]) ++ (with pkgs.darwin; [
        dyld Libsystem CF cctools ICU libiconv locale libxml2-nopython.out
      ]);
  
      overrides = lib.composeExtensions persistent (self: super: {
  
negative.code:       llvmPackages_7 = super.llvmPackages_7 // (let
          tools = super.llvmPackages_7.tools.extend (llvmSelf: _: {
            clang-unwrapped = llvmPackages_7.clang-unwrapped.override { llvm = llvmSelf.llvm; };
            llvm = llvmPackages_7.llvm.override { inherit libxml2; };
          });
          libraries = super.llvmPackages_7.libraries.extend (llvmSelf: _: {
            inherit (llvmPackages_7) libcxx libcxxabi compiler-rt;
  