anchor.diff:  @set vsenv=%vsenv14%
   @if %toolset%==15 set vsenv=%vsenv15%
   @set PATH=%mesa%flexbison\;%PATH%
  +@TITLE Building Mesa3D %abi%
   
   :build_llvm
   @set /p buildllvm=Begin LLVM build. Only needs to run once for each ABI and version. Proceed (y/n):
  
positive.code: @if %abi%==x64 set modtoolchainabi=%modtoolchainabi%2
  @if %modtoolchainabi%==12 set toolchain=%toolchain% Win64
  @cd %llvmbuildsys%
  @cmake -G "%toolchain%" -DLLVM_TARGETS_TO_BUILD=X86 -DCMAKE_BUILD_TYPE=Release -DLLVM_USE_CRT_RELEASE=MT -DLLVM_ENABLE_RTTI=1 -DLLVM_ENABLE_TERMINFO=OFF -DCMAKE_INSTALL_PREFIX=../%abi% ..
  @echo.
  @pause
  @echo.
  
negative.code: @if %abi%==x64 set altabi=%longabi%
  @set minabi=32
  @if %abi%==x64 set minabi=64
  @set hostabi=x86
  @set vsenv="%ProgramFiles%
  @if NOT "%ProgramW6432%"=="" set hostabi=x64
  @if NOT "%ProgramW6432%"=="" set vsenv=%vsenv% (x86)
  @set vsenv15=%vsenv%\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvars%minabi%.bat"
  @set vsenv14="%VS140COMNTOOLS%..\..\VC\bin\vcvars%minabi%.bat"
  