anchor.diff:  @if /i NOT %mingw%==y GOTO build_with_vs
   
   :build_with_mingw
  -@set buildmingw=toolchain=crossmingw
  +@set mesatoolchain=crossmingw
   @copy "%gcc%\%altabi%-w64-mingw32-gcc-ar.exe" "%gcc%\%altabi%-w64-mingw32-ar.exe"
   @copy "%gcc%\%altabi%-w64-mingw32-gcc-ranlib.exe" "%gcc%\%altabi%-w64-mingw32-ranlib.exe"
   @call "%msys2%" -use-full-path
  
positive.code: @cd "%mesa%mesa"
  @RD /S /Q build\windows-%longabi%
  @set /p openswr=Do you want to build OpenSWR drivers? (y=yes):
  @set buildswr=
  @if /i %openswr%==y @set buildswr=swr=1
  @set mingw=n
  @set mingwtest=0
  @if EXIST "%gcc%" @set mingwtest=1
  
negative.code: @if %abi%==x64 set minabi=64
  @set vsenv=%ProgramFiles%
  @if NOT "%ProgramW6432%"=="" set vsenv=%vsenv% (x86)
  @set vsenv15=%vsenv%\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvars%minabi%.bat
  @if EXIST "%vsenv15%" @set toolchain=Visual Studio 15 2017
  @if NOT EXIST "%vsenv15%" @set toolchain=Visual Studio 14
  @set vsenv14=%VS140COMNTOOLS%..\..\VC\bin\vcvars%minabi%.bat
  @if %abi%==x64 @set toolchain=%toolchain% Win64
  @set gcc=%mesa%mingw-w64-%abi%\mingw%minabi%\bin
  @set vsenvloaded=0
  