anchor.diff:  @rem Check environment
  -@IF %flexstate%==0 (
  -@echo Flex and bison are required to build Mesa3D.
  -GOTO skipmesa
  -)
  -@if NOT EXIST mesa if %gitstate%==0 (
  -@echo Fatal: Both Mesa3D code and Git are missing. At least one is required. Execution halted.
  -@GOTO skipmesa
  -)
  +@IF %flexstate%==0 echo Flex and bison are required to build Mesa3D.
  +@IF %flexstate%==0 GOTO skipmesa
  +@if NOT EXIST mesa if %gitstate%==0 echo Fatal: Both Mesa3D code and Git are missing. At least one is required. Execution halted.
  +@if NOT EXIST mesa if %gitstate%==0 GOTO skipmesa
   
   @rem Hide Meson support behind a parametter as it doesn't work yet. Also Meson MSYS2 Mingw-w64 build is completely unexplored
   @rem so disable it as well.
  
positive.code: @IF %toolchain%==gcc if %pythonver% GEQ 3 echo Mesa3D build: Unimplemented code path.
  @IF %toolchain%==gcc if %pythonver% GEQ 3 GOTO skipmesa
  
  @IF %pythonver% GEQ 3 IF %pkgconfigstate%==0 echo pkg-config is required to build Mesa3D with Meson. You can either use mingw-w64 or pkgconfiglite distribution, but mingw-w64 is the only up-to-date distribution.
  @IF %pythonver% GEQ 3 IF %pkgconfigstate%==0 GOTO skipmesa
  
  @REM Aquire Mesa3D source code if missing.
  
negative.code: @if NOT EXIST mesa IF %pythonver%==2 set mesarepo=https://gitlab.freedesktop.org/mesa/mesa.git
  @if NOT EXIST mesa IF %pythonver% GEQ 3 set mesarepo=https://gitlab.freedesktop.org/dbaker/mesa.git
  @if NOT EXIST mesa IF %pythonver% GEQ 3 set branch=meson-windows
  @if NOT EXIST mesa git clone --recurse-submodules --depth=1 --branch=%branch% %mesarepo% mesa
  @if NOT EXIST mesa echo.
  
  @if EXIST mesa if /i NOT "%buildmesa%"=="y" set /p buildmesa=Begin mesa build. Proceed (y/n):
  @if EXIST mesa if /i "%buildmesa%"=="y" echo.
  