Portability improvements
Produce Zip64 format when needed for --zip (>= 4 GiB)
Make -no-name compatible with gzip, add --time option
Add -m as a short option for --no-time
Check run-time zlib version to handle weak linking
Fix a concurrent read bug in --list operation
Process options first, for gzip compatibility
Add --synchronous (-Y) option to force device write
Disallow an empty suffix (e.g. --suffix '')
Return an exit code of 1 if any issues are encountered
Fix sign error in compression reduction percentage