anchor.diff:  
       allowedRequisites =
         [ bootstrapTools ] ++
  -      (with pkgs; [ icu bash libcxx libcxxabi ]) ++
  +      (with pkgs; [ xz.bin xz.out icu.out bash libcxx libcxxabi ]) ++
         (with pkgs.darwin; [ dyld Libsystem locale ]);
   
       overrides = persistent2;
  
positive.code:     };
  
      allowedRequisites = (with pkgs; [
        xz libcxx libcxxabi icu gmp gnumake findutils bzip2 llvm zlib libffi
        coreutils ed diffutils gnutar gzip ncurses gnused bash gawk
        gnugrep llvmPackages.clang-unwrapped patch pcre binutils-raw binutils gettext
      ]) ++ (with pkgs.darwin; [
        dyld Libsystem CF cctools libiconv locale
      ]);
  
negative.code: 
      allowedRequisites =
        [ bootstrapTools ] ++
        (with pkgs; [ xz.bin xz.out libcxx libcxxabi icu.out ]) ++
        (with pkgs.darwin; [ dyld Libsystem CF locale ]);
  
      overrides = persistent1;
  