anchor.diff:  
   :zipfile
   
  -set ZipTool=%InfoZipDir%\zip.exe
   if exist %ZipFile% (
     echo %ZipFile% already exists.
   ) else (
  
positive.code: set GdalPackageUrl=%GdalPackageSite%/Download.aspx?file=%GdalPackageName%
  set DownloadDir=download
  set DownloadedPackage=%DownloadDir%\%GdalPackageName%
  set DistributionDir=dist
  set ZipFile=gdal-1-9-0-csharp-win64.zip
  set InfoZipDir=..\..\..\..\Info-ZIP
  set UnzipTool=%InfoZipDir%\unzip.exe
  
  call :download
  call :extract
  
negative.code: )
  
  echo Downloading %GdalPackageName% ...
  %DownloadTool% %GdalPackageUrl% %DownloadedPackage%
  goto :eof
  
  