Initial support of make format for Windows

There are couple of caviats currently:

- The script requires system-wide Python 3 available in the current
  search PATH as python.exe.

  This will get addressed soon by distributing unpacked Python binary
  in our libraries.

- Since the libraries folder is to be known, this requires to have
  MSVC detected. Not too bad, since formatting is still way slower
  than detection, but still doesn't feel ideal.

build_files/windows/format.cmd

@@ -0,0 +1,10 @@
+REM TODO(sergey): Switch to Python from libraries when available.
+set PYTHON="python.exe"
+set FORMAT_PATHS=%BLENDER_DIR%\source\tools\utils\clang_format_paths.py
+
+REM The formatting script expects clang-format to be in the current PATH.
+set PATH=%BUILD_VS_LIBDIR%\llvm\bin;%PATH%
+
+%PYTHON% %FORMAT_PATHS% --expand-tabs
+
+:EOF

build_files/windows/parse_arguments.cmd

@@ -81,6 +81,8 @@ if NOT "%1" == "" (
 		set MUST_CLEAN=1
 	) else if "%1" == "verbose" (
 		set VERBOSE=1
+	) else if "%1" == "format" (
+		set FORMAT=1
 	) else (
 		echo Command "%1" unknown, aborting!
 		exit /b 1

build_files/windows/reset_variables.cmd

@@ -27,3 +27,4 @@ set CLANG_CMAKE_ARGS=
 set ASAN_CMAKE_ARGS=
 set WITH_PYDEBUG=
 set PYDEBUG_CMAKE_ARGS=
+set FORMAT=

make.bat

@@ -47,13 +47,18 @@ if "%BUILD_VS_YEAR%" == "" (
 	)
 )
 
+call "%BLENDER_DIR%\build_files\windows\check_libraries.cmd"
+if errorlevel 1 goto EOF
+
+if "%FORMAT%" == "1" (
+	call "%BLENDER_DIR%\build_files\windows\format.cmd"
+	goto EOF
+)
+
 call "%BLENDER_DIR%\build_files\windows\set_build_dir.cmd"
 
 echo Building blender with VS%BUILD_VS_YEAR% for %BUILD_ARCH% in %BUILD_DIR%
 
-call "%BLENDER_DIR%\build_files\windows\check_libraries.cmd"
-if errorlevel 1 goto EOF
-
 call "%BLENDER_DIR%\build_files\windows\check_submodules.cmd"
 if errorlevel 1 goto EOF