anchor.diff:  IF DEFINED ProgramFiles(x86) IF EXIST "%ProgramFiles(x86)%\nodejs" ECHO copying to "%ProgramFiles(x86)%\nodejs\node.exe" && COPY /Y node.exe "%ProgramFiles(x86)%\nodejs\"
   IF %ERRORLEVEL% NEQ 0 GOTO ERROR
   
  -
  -ECHO clear out node-gyp header cache
  +:: this is not needed on a fresh machine without previous installs
  +:: but is important on a machine that already has compiled for a given
  +:: node version. So, we have to clear to ensure that the Visual Studio 2015
  +:: binaries are used rather than the ones from joyent (which are built with Visual Studio 2013)
  +ECHO clear out node-gyp binary cache to ensure vs 2015 binaries are linked
   IF "%msvs_toolset%" == "14" IF EXIST %USERPROFILE%\.node-gyp rd /s /q %USERPROFILE%\.node-gyp
   
   ECHO activating VS command prompt
  
positive.code: IF EXIST mapnik-sdk (ECHO already extracted) ELSE (7z -y x mapnik-sdk.7z | %windir%\system32\FIND "ing archive")
  IF %ERRORLEVEL% NEQ 0 GOTO ERROR
  
  
  ::replace installed node.exe with Mapbox node.exe
  ::install node version per visual studio toolset
  IF EXIST node.exe ECHO found local node.exe, deleting ... && DEL /F node.exe
  IF %ERRORLEVEL% NEQ 0 GOTO ERROR
  SET ARCHPATH=
  IF /I %platform% == x64 (SET ARCHPATH=x64/)
  SET NODE_URL=https://mapbox.s3.amazonaws.com/node-cpp11/v%nodejs_version%/%ARCHPATH%node.exe
  
negative.code: 
  ECHO =========== %~f0 ===========
  
  :: use 64 bit python if platform is 64 bit
  IF /I "%PLATFORM%" == "x64" set PATH=C:\Python27-x64;%PATH%
  :: put 7z on path (needed for unpacking mapnik sdk)
  SET PATH=C:\Program Files\7-Zip;%PATH%
  
  :: TODO - dist/dev/ is intended for dev releases of mapnik
  :: We ideally want to get in the habit of only using Mapnik official releases
  :: which will be uploaded to dist/
  SET MAPNIK_SDK_URL=https://mapnik.s3.amazonaws.com/dist/dev/mapnik-win-sdk-v%MAPNIK_GIT%-%platform%-%msvs_toolset%.0.7z
  ECHO fetching mapnik sdk^: %MAPNIK_SDK_URL%
  IF EXIST mapnik-sdk.7z (ECHO already downloaded) ELSE (powershell Invoke-WebRequest "${env:MAPNIK_SDK_URL}" -OutFile mapnik-sdk.7z)
  