anchor.diff:  echo -v^|--vs-version      --Set Visual Studio version to configure. Must be one of: vs2015, vs2017, vs2019
   echo -p^|--pthreads-home   --Set pthreads-win32 home directory
   echo -w^|--pcap-sdk        --Set WinPcap/Npcap SDK directory
  +echo -z^|--zstd-sdk        --Set ZStd SDK directory
   echo -h^|--help            --Display this help message and exits. No further actions are performed
   echo.
   :: done printing, exit
  
positive.code: :CASE-v
  :CASE--vs-version
      :: this argument must have a parameter. If no parameter was found goto GETOPT_REQUIRED_PARAM and exit
      if "%2"=="" goto GETOPT_REQUIRED_PARAM %1
      :: verify the VS version provided is one of the supported versions
      if "%2" NEQ "vs2015" if "%2" NEQ "vs2017" if "%2" NEQ "vs2019" call :GETOPT_ERROR "Visual Studio version must be one of: vs2015, vs2017, vs2019" & exit /B 3
      :: if all went well, set the VS_VERSION variable
  
negative.code: :: ask user about using zstd
  echo ZStd compression support may be added when compiling PcapPlusPlus.
  echo For downloading ZStd SDK (developer's pack) please go to https://github.com/facebook/zstd/releases
  :while4
  :: ask the user to type ZStd SDK dir
  set /p ZSTD_HOME=    Please specify ZStd SDK path or type "no" to build without ZStd: %=%
  if "%USE_ZSTD%" EQU "no" goto skipWhile4
  :: if input dir doesn't exist print an error to the user and go back to previous line
  if not exist "%ZSTD_HOME%"\ (echo Directory does not exist!! && goto while4)
  set USE_ZSTD=USE_Z_STD;
  