build: vcbuild uses default Python, not Py2

vcbuild now searches for the first python.exe found, and uses it, where
it used to look for Python 2 first.

PR-URL: #30091
Reviewed-By: Christian Clauss <cclauss@me.com>
Reviewed-By: João Reis <reis@janeasystems.com>
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

tools/msvs/find_python.cmd

@@ -3,27 +3,6 @@
 echo Looking for Python
 setlocal enabledelayedexpansion
 
-:: To remove the preference for Python 2, but still support it, just remove
-:: the 5 blocks marked with "Python 2:" and the support warnings
-
-:: Python 2: If python.exe is in %Path%, use if it's Python 2
-FOR /F "delims=" %%a IN ('where python.exe 2^> NUL') DO (
-  SET need_path=0
-  SET p=%%~dpa
-  CALL :validate-v2
-  IF NOT ERRORLEVEL 1 GOTO :found-python2
-  GOTO :done-path-v2
-)
-:done-path-v2
-
-:: Python 2: Query the 3 locations mentioned in PEP 514 for a python2 InstallPath
-FOR %%K IN ( "HKCU\Software", "HKLM\SOFTWARE", "HKLM\Software\Wow6432Node") DO (
-  SET need_path=1
-  CALL :find-versions-v2 %%K
-  IF NOT ERRORLEVEL 1 CALL :validate-v2
-  IF NOT ERRORLEVEL 1 GOTO :found-python2
-)
-
 :: Use python.exe if in %PATH%
 set need_path=0
 for /f "delims=" %%a in ('where python.exe 2^> nul') do (
@@ -41,14 +20,6 @@ for %%k in ( "HKCU\Software", "HKLM\SOFTWARE", "HKLM\Software\Wow6432Node") do (
 goto :no-python
 
 
-:: Python 2: Find Python 2 installations in a registry location
-:find-versions-v2
-for /f "delims=" %%a in ('reg query "%~1\Python\PythonCore" /f * /k 2^> nul ^| findstr /r ^^HK ^| findstr "\\2\."') do (
-  call :read-installpath %%a
-  if not errorlevel 1 exit /b 0
-)
-exit /b 1
-
 :: Find Python installations in a registry location
 :find-versions
 for /f "delims=" %%a in ('reg query "%~1\Python\PythonCore" /f * /k 2^> nul ^| findstr /r ^^HK') do (
@@ -73,32 +44,11 @@ for /f "skip=2 tokens=1* delims=)" %%a in ('reg query "%1\InstallPath" /ve /t RE
 )
 exit /b 1
 
-
-:: Python 2: Check if %p% holds a path to a real python2 executable
-:validate-v2
-IF NOT EXIST "%p%\python.exe" EXIT /B 1
-:: Check if %p% is python2
-"%p%\python.exe" -V 2>&1 | findstr /R "^Python.2.*" > NUL
-EXIT /B %ERRORLEVEL%
-
-
-:: Python 2:
-:found-python2
-echo Python 2 found in %p%\python.exe
-set pyver=2
-goto :done
-
 :found-python
 echo Python found in %p%\python.exe
-echo WARNING: Python 3 is not yet fully supported, to avoid issues Python 2 should be installed.
-set pyver=3
-goto :done
-
-:done
 endlocal ^
   & set "pt=%p%" ^
-  & set "need_path_ext=%need_path%" ^
-  & set "VCBUILD_PYTHON_VERSION=%pyver%"
+  & set "need_path_ext=%need_path%"
 set "VCBUILD_PYTHON_LOCATION=%pt%\python.exe"
 if %need_path_ext%==1 set "PATH=%pt%;%PATH%"
 set "pt="

vcbuild.bat

@@ -688,9 +688,6 @@ goto exit
 
 :create-msvs-files-failed
 echo Failed to create vc project files.
-if %VCBUILD_PYTHON_VERSION%==3 (
-  echo Python 3 is not yet fully supported, to avoid issues Python 2 should be installed.
-)
 del .used_configure_flags
 goto exit