anchor.diff:  @pip freeze > requirements.txt
   @pip install -r requirements.txt --upgrade
   @del requirements.txt
  -@set restartcond=0
  -@set vs2017toolset=n
   @echo.
  -@if EXIST "%vsenv15%" set /p vs2017toolset=Do you want to build with Visual Studio 2017 toolset (y/n) - WARNING, this is a hack, it will break if Mesa MSVC build gets support for LLVM 4.0 before Scons gets support for MSVC 2017:
  -@if /i %vs2017toolset%==y @set vsenvloaded=%vsenvloaded%15
  -@if /i NOT %vs2017toolset%==y @set vsenvloaded=%vsenvloaded%14
  -@if %vsenvloaded%==01514 set restartcond=1
  +@if %vsenvloaded%==0 (
  +@call "%vsenv%"
   @echo.
  -@if %vsenvloaded%==015 call "%vsenv15%"
  -@if %vsenvloaded%==014 call "%vsenv14%"
  -@if %restartcond%==1 (
  -@echo.
  -@echo A Visual Studio build environment is already loaded. The script will now restart to flush loaded environment.
  -@pause
  -@GOTO exit
   )
  -@echo.
   
   :build_mesa_exec
   @python "%mesa%Python\%abi%\Scripts\scons.py" build=release platform=windows machine=%longabi% toolchain=%mesatoolchain% swr=%buildswr% libgl-gdi
  
positive.code: @echo.
  @md cmake-%abi%
  @cd cmake-%abi%
  @if EXIST "%vsenv15%" (
  @set vsenvloaded=%vsenvloaded%15
  @set toolchain=Visual Studio 15 2017
  @call "%vsenv15%"
  )
  @if NOT EXIST "%vsenv15%" (
  @set vsenvloaded=%vsenvloaded%14
  @set toolchain=Visual Studio 14
  @call "%vsenv14%"
  )
  @if %abi%==x64 @set toolchain=%toolchain% Win64
  @set PATH=%mesa%cmake\%abi%\bin\;%PATH%
  @echo.
  
negative.code: @if %abi%==x64 set minabi=64
  @set vsenv=%ProgramFiles%
  @if NOT "%ProgramW6432%"=="" set vsenv=%vsenv% (x86)
  @set vsenv=%vsenv%\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvars%minabi%.bat
  @set toolchain=Visual Studio 15 2017
  @if NOT EXIST "%vsenv%" (
  @set vsenv=%VS140COMNTOOLS%..\..\VC\bin\vcvars%minabi%.bat
  @set toolchain=Visual Studio 14
  )
  @set gcc=%mesa%mingw-w64-%abi%\mingw%minabi%\bin
  @set vsenvloaded=0
  @set dxtnbuilt=0
  