bpo-43915: Add PCbuild/blurb.bat to simplify Windows contributors (GH-25528)

Author: zooba

PCbuild/blurb.bat

@@ -0,0 +1,28 @@
+@echo off
+rem
+rem Runs the blurb tool. If necessary, will install Python and/or blurb.
+rem
+rem Pass "--update"/"-U" as the first argument to update blurb.
+rem
+
+call "%~dp0find_python.bat" %PYTHON%
+if ERRORLEVEL 1 (echo Cannot locate python.exe on PATH or as PYTHON variable & exit /b 3)
+
+if "%1" EQU "--update" (%PYTHON% -m pip install -U blurb && shift)
+if "%1" EQU "-U" (%PYTHON% -m pip install -U blurb && shift)
+
+%PYTHON% -m blurb %1 %2 %3 %4 %5 %6 %7 %8 %9
+if ERRORLEVEL 1 goto :install_and_retry
+exit /B 0
+
+:install_and_retry
+rem Before reporting the error, make sure that blurb is actually installed.
+rem If not, install it first and try again.
+set _ERR=%ERRORLEVEL%
+%PYTHON% -c "import blurb"
+if NOT ERRORLEVEL 1 exit /B %_ERR%
+echo Installing blurb...
+%PYTHON% -m pip install blurb
+if ERRORLEVEL 1 exit /B %ERRORLEVEL%
+%PYTHON% -m blurb %*
+exit /B