anchor.diff:  function deflateCopy(var dest, source: z_stream): Integer;
   function deflateReset(var strm: z_stream): Integer;
   function deflateParams(var strm: z_stream; level, strategy: Integer): Integer;
  +function deflateTune(var strm: z_stream; good_length, max_lazy, nice_length, max_chain: Integer): Integer;
   function deflateBound(var strm: z_stream; sourceLen: LongInt): LongInt;
   function deflatePending(var strm: z_stream; var pending: Integer; var bits: Integer): Integer;
   function deflatePrime(var strm: z_stream; bits, value: Integer): Integer;
  +function deflateSetHeader(var strm: z_stream; head: gz_header): Integer;
   function inflateInit2(var strm: z_stream; windowBits: Integer): Integer;
   function inflateSetDictionary(var strm: z_stream; const dictionary: PChar;
                                 dictLength: Integer): Integer;
   function inflateSync(var strm: z_stream): Integer;
   function inflateCopy(var dest, source: z_stream): Integer;
   function inflateReset(var strm: z_stream): Integer;
  +function inflateReset2(var strm: z_stream; windowBits: Integer): Integer;
  +function inflatePrime(var strm: z_stream; bits, value: Integer): Integer;
  +function inflateMark(var strm: z_stream): LongInt;
  +function inflateGetHeader(var strm: z_stream; var head: gz_header): Integer;
   function inflateBackInit(var strm: z_stream;
                            windowBits: Integer; window: PChar): Integer;
   function inflateBack(var strm: z_stream; in_fn: in_func; in_desc: Pointer;
  
positive.code:     data_type: Integer;   (* best guess about the data type: ascii or binary *)
      adler: LongInt;       (* adler32 value of the uncompressed data *)
      reserved: LongInt;    (* reserved for future use *)
    end;
  
  (* constants *)
  
negative.code: 
  (* checksum functions *)
  function adler32(adler: LongInt; const buf: PChar; len: Integer): LongInt;
  function adler32_combine(adler1, adler2, len2: LongInt): LongInt;
  function crc32(crc: LongInt; const buf: PChar; len: Integer): LongInt;
  function crc32_combine(crc1, crc2, len2: LongInt): LongInt;
  
  (* various hacks, don't look :) *)
  function deflateInit_(var strm: z_stream; level: Integer;
  