anchor.diff:    inherit buildInputs;
     C_INCLUDE_PATH = concatStringsSep ":" (map (p: "${p}/include") buildInputs);
     LIBRARY_PATH = concatStringsSep ":" (map (p: "${p}/lib") buildInputs);
  -  configureFlags = ''${if stdenv.isDarwin then "" else " --enable-shared"} --with-wctype-functions'';
  +  configureFlags = ''${if stdenv.isDarwin then "" else " --enable-shared"} --with-threads --enable-unicode --with-wctype-functions'';
   
     preConfigure = ''
       # Purity.
  
positive.code: 
  let
  
    buildInputs =
      optional (stdenv ? gcc && stdenv.gcc.libc != null) stdenv.gcc.libc ++
      [bzip2]
  
negative.code:     readlineSupport = readline != null;
      opensslSupport = openssl != null;
      tkSupport = (tk != null) && (tcl != null);
      libPrefix = "python${majorVersion}";
    };
  
    meta = {
  