anchor.diff:  @set /p buildllvm=Begin LLVM build. Only needs to run once for each ABI and version. Proceed (y/n):
   @if /I NOT "%buildllvm%"=="y" GOTO build_dxtn
   @echo.
  -@cd "%mesa%llvm"
  +@cd %mesa%llvm
   @if EXIST %abi% RD /S /Q %abi%
   @if EXIST cmake-%abi% RD /S /Q cmake-%abi%
   @md cmake-%abi%
  
positive.code: @set mesa=%cd%\
  @set abi=x86
  @set /p x64=Do you want to build for x64?(y/n) Otherwise build for x86: 
  @if /I "%x64%"=="y" set abi=x64
  
negative.code: @if EXIST %vsenv15% set toolset=15
  @set ninja=n
  @set oldtoolset=n
  @if EXIST %mesa%ninja set ninja=1
  @if EXIST %vsenv15% set ninja=%ninja%2
  @if %ninja%==12 set /p oldtoolset=Build with MSVC 2015 backward compatibility toolset, alternative solution for LLVM 3.9.1 build with Visual Studio 2017 (y/n):
  @if %ninja%==12 echo.
  