Hi Evengy, the issue is not related to System.ZLib but to uROZLib.
The definition of ZInternalCompressStream and ZInternalDecompressStream is wrong.
It should be:
procedure ZInternalCompressStream(var zstream: TZStreamRec; inStream, outStream: TStream);
procedure ZInternalDecompressStream(var zstream: TZStreamRec; inStream, outStream: TStream);
That is, you need to include the var modifier before the zstream parameter. If you don’t, the copy of the record may include some trash data between the aligned fields and this leads to the failure of the inflate procedure.
Once you modify the procedure definition everything works like a charm with the iOS 64 bit compiler.
Regards