anchor.diff:  @del requirements.txt
   
   @set /p buildllvm=Begin LLVM build. Only needs to run once for each ABI and version. Proceed y/n? 
  -@if /I %buildllvm%==y GOTO build_llvm
  -@if /I NOT %buildllvm%==y GOTO Next
  +@if /I NOT %buildllvm%==y GOTO build_dxtn
   
   :build_llvm
   @cd %mesa%llvm
  
positive.code: @msbuild /p:Configuration=Release INSTALL.vcxproj
  @pause
  
  :Next
  @set /p buildmesa=Begin mesa build. Proceed y/n? 
  @if /i %buildmesa%==y GOTO build_mesa
  @if /i NOT %buildmesa%==y @exit
  
  :build_mesa
  @set LLVM=%mesaunix%llvm/%abi%
  @cd %mesa%mesa
  @set /p openswr=Do you want to build OpenSWR drivers? (y=yes):
  @set buildswr=
  @if /i %openswr%==y @set buildswr=swr=1
  @cmd /k "scons build=release platform=windows machine=%longabi% %buildswr% libgl-gdi"
negative.code: @if /I %x64%==y @set abi=x64
  @set longabi=%abi%
  @if %abi%==x64 @set longabi=x86_64
  @set toolchain=Visual Studio 15 2017
  @if %abi%==x64 @set toolchain=%toolchain% Win64
  @set altabi=i686
  @if %abi%==x64 @set altabi=%longabi%
  @set minabi=32
  @if %abi%==x64 set minabi=64
  @if "%ProgramW6432%"=="" set vsenv=%ProgramFiles%
  @if NOT "%ProgramW6432%"=="" set vsenv=%ProgramFiles% (x86)
  @if %abi%==x86 set gcc=%vsenv%
  @if %abi%==x64 set gcc=%ProgramFiles%
  @set vsenv="%vsenv%\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\
  @if %abi%==x86 set vsenv=%vsenv%\vcvars32.bat"
  @if %abi%==x64 set vsenv=%vsenv%\vcvars64.bat"
  @call %vsenv%
  
  @if %abi%==x86 set gcc=%gcc%\mingw-w64\%altabi%-%x86gcc%-%x86threading%-%x86except%-rt_v%x86mingwver%-rev%x86mingwrev%
  @if %abi%==x64 set gcc=%gcc%\mingw-w64\%altabi%-%x64gcc%-%x64threading%-%x64except%-rt_v%x64mingwver%-rev%x64mingwrev%
  
  @set PATH=%mesa%flexbison\;%mesa%m4\%abi%\bin\;%mesa%Python\%abi%\;%mesa%Python\%abi%\Scripts\;%mesa%cmake\%abi%\bin\;%PATH%
  @if EXIST "%gcc%" set PATH=%gcc%\mingw%minabi%\bin\;%PATH%
  
  @pip install -U mako
  @pip freeze > requirements.txt
  