anchor.diff:  if errorlevel 1 exit 1
   cd %PREFIX%
   %PYTHON% %SRC_DIR%/packaging/setup-generic.py install
  -if errorlevel 1 exit 1+if errorlevel 1 exit 1
  
positive.code: @REM Build Windows package from tracktable source
  set "CXX=cl.exe"
  set "CC=cl.exe"
  echo ENVIRONMENT_VARS
  set
  mkdir build
  
negative.code:  -DBUILD_DOCUMENTATION=OFF^
   -DPython3_EXECUTABLE:FILEPATH=%PYTHON%^
   -DPython3_ROOT_DIR:PATH=%PREFIX%^
   -DCMAKE_CXX_COMPILER=cl.exe^
   %SRC_DIR%^
   -LA
  if errorlevel 1 exit 1
  