anchor.diff:  function VerifyZip(Strm : TStream) : TAbArchiveType;
   { determine if stream appears to be in PkZip format }
   var
  -  Footer       : TAbZipDirectoryFileFooter;
  +  Footer       : TAbZipEndOfCentralDirectoryRecord;
     Sig          : LongInt;
     TailPosition : int64;
     StartPos     : int64;
  
positive.code: 
    PAbIntegerArray = ^TAbIntegerArray;
    TAbIntegerArray = array[0..65535 div sizeof(integer)-1] of integer;
  
    TAbFollower =                      {used to expand reduced files}
      packed record
  
negative.code: 
          {if it's as valid a tail as we can check here...}
          CommentLen := -Offset - (TestPos - Buffer + sizeof(TailRec));
          if (TailRec.CommentLength <= CommentLen) then begin
  
            {calculate its position and exit}
            Result := Result + (TestPos - Buffer);
  