FindPython: use 'sysconfig' as alternate to 'distutils.sysconfig'

To support any python installation, if package 'distutils.sysconfig'
is not available, try to use package 'sysconfig'.

Fixes: #20502

Modules/FindPython/Support.cmake

@@ -321,7 +321,7 @@ function (_PYTHON_GET_CONFIG_VAR _PYTHON_PGCV_VALUE NAME)
 
   if (_${_PYTHON_PREFIX}_EXECUTABLE AND NOT CMAKE_CROSSCOMPILING)
     if (NAME STREQUAL "PREFIX")
-      execute_process (COMMAND "${_${_PYTHON_PREFIX}_EXECUTABLE}" -c "import sys; from distutils import sysconfig; sys.stdout.write(';'.join([sysconfig.PREFIX,sysconfig.EXEC_PREFIX,sysconfig.BASE_EXEC_PREFIX]))"
+      execute_process (COMMAND "${_${_PYTHON_PREFIX}_EXECUTABLE}" -c "import sys\ntry:\n   from distutils import sysconfig\n   sys.stdout.write(';'.join([sysconfig.PREFIX,sysconfig.EXEC_PREFIX,sysconfig.BASE_EXEC_PREFIX]))\nexcept Exception:\n   import sysconfig\n   sys.stdout.write(';'.join([sysconfig.get_config_var('base') or '', sysconfig.get_config_var('installed_base') or '']))"
                        RESULT_VARIABLE _result
                        OUTPUT_VARIABLE _values
                        ERROR_QUIET
@@ -332,16 +332,23 @@ function (_PYTHON_GET_CONFIG_VAR _PYTHON_PGCV_VALUE NAME)
         list (REMOVE_DUPLICATES _values)
       endif()
     elseif (NAME STREQUAL "INCLUDES")
-      execute_process (COMMAND "${_${_PYTHON_PREFIX}_EXECUTABLE}" -c "import sys; from distutils import sysconfig; sys.stdout.write(';'.join([sysconfig.get_python_inc(plat_specific=True),sysconfig.get_python_inc(plat_specific=False)]))"
+      if (WIN32)
+        set (_scheme "nt")
+      else()
+        set (_scheme "posix_prefix")
+      endif()
+      execute_process (COMMAND "${_${_PYTHON_PREFIX}_EXECUTABLE}" -c "import sys\ntry:\n   from distutils import sysconfig\n   sys.stdout.write(';'.join([sysconfig.get_python_inc(plat_specific=True),sysconfig.get_python_inc(plat_specific=False)]))\nexcept Exception:\n   import sysconfig\n   sys.stdout.write(';'.join([sysconfig.get_path('platinclude'),sysconfig.get_path('platinclude','${_scheme}'),sysconfig.get_path('include'),sysconfig.get_path('include','${_scheme}')]))"
                        RESULT_VARIABLE _result
                        OUTPUT_VARIABLE _values
                        ERROR_QUIET
                        OUTPUT_STRIP_TRAILING_WHITESPACE)
       if (_result)
         unset (_values)
+      else()
+        list (REMOVE_DUPLICATES _values)
       endif()
     elseif (NAME STREQUAL "SOABI")
-      execute_process (COMMAND "${_${_PYTHON_PREFIX}_EXECUTABLE}" -c "import sys; from distutils import sysconfig;sys.stdout.write(';'.join([sysconfig.get_config_var('SOABI') or '',sysconfig.get_config_var('EXT_SUFFIX') or '']))"
+      execute_process (COMMAND "${_${_PYTHON_PREFIX}_EXECUTABLE}" -c "import sys\ntry:\n   from distutils import sysconfig\n   sys.stdout.write(';'.join([sysconfig.get_config_var('SOABI') or '',sysconfig.get_config_var('EXT_SUFFIX') or '']))\nexcept Exception:\n   import sysconfig;sys.stdout.write(';'.join([sysconfig.get_config_var('SOABI') or '',sysconfig.get_config_var('EXT_SUFFIX') or '']))"
                        RESULT_VARIABLE _result
                        OUTPUT_VARIABLE _soabi
                        ERROR_QUIET
@@ -349,14 +356,15 @@ function (_PYTHON_GET_CONFIG_VAR _PYTHON_PGCV_VALUE NAME)
       if (_result)
         unset (_values)
       else()
-        list (GET _soabi 0 _values)
-        if (NOT _values)
-          # try to compute SOABI from EXT_SUFFIX
-          list (GET _soabi 1 _values)
-          if (_values)
-            # clean-up: remove prefix character and suffix
-            string (REGEX REPLACE "^[.-](.+)(${CMAKE_SHARED_LIBRARY_SUFFIX}|\\.(so|pyd))$" "\\1" _values "${_values}")
+        foreach (_item IN LISTS _soabi)
+          if (_item)
+            set (_values "${_item}")
+            break()
           endif()
+        endforeach()
+        if (_values)
+          # clean-up: remove prefix character and suffix
+          string (REGEX REPLACE "^[.-](.+)(${CMAKE_SHARED_LIBRARY_SUFFIX}|\\.(so|pyd))$" "\\1" _values "${_values}")
         endif()
       endif()
     else()
@@ -364,7 +372,7 @@ function (_PYTHON_GET_CONFIG_VAR _PYTHON_PGCV_VALUE NAME)
       if (NAME STREQUAL "CONFIGDIR")
         set (config_flag "LIBPL")
       endif()
-      execute_process (COMMAND "${_${_PYTHON_PREFIX}_EXECUTABLE}" -c "import sys; from distutils import sysconfig; sys.stdout.write(sysconfig.get_config_var('${config_flag}'))"
+      execute_process (COMMAND "${_${_PYTHON_PREFIX}_EXECUTABLE}" -c "import sys\ntry:\n   from distutils import sysconfig\n   sys.stdout.write(sysconfig.get_config_var('${config_flag}'))\nexcept Exception:\n   import sysconfig\n   sys.stdout.write(sysconfig.get_config_var('${config_flag}'))"
                        RESULT_VARIABLE _result
                        OUTPUT_VARIABLE _values
                        ERROR_QUIET
@@ -392,6 +400,10 @@ function (_PYTHON_GET_CONFIG_VAR _PYTHON_PGCV_VALUE NAME)
     list (REMOVE_DUPLICATES _values)
   endif()
 
+  if (WIN32 AND NAME MATCHES "^(PREFIX|CONFIGDIR|INCLUDES)$")
+    file (TO_CMAKE_PATH "${_values}" _values)
+  endif()
+
   set (${_PYTHON_PGCV_VALUE} "${_values}" PARENT_SCOPE)
 endfunction()
 
@@ -1381,7 +1393,7 @@ if ("Interpreter" IN_LIST ${_PYTHON_PREFIX}_FIND_COMPONENTS)
         endif()
 
         # retrieve various package installation directories
-        execute_process (COMMAND "${_${_PYTHON_PREFIX}_EXECUTABLE}" -c "import sys; from distutils import sysconfig;sys.stdout.write(';'.join([sysconfig.get_python_lib(plat_specific=False,standard_lib=True),sysconfig.get_python_lib(plat_specific=True,standard_lib=True),sysconfig.get_python_lib(plat_specific=False,standard_lib=False),sysconfig.get_python_lib(plat_specific=True,standard_lib=False)]))"
+        execute_process (COMMAND "${_${_PYTHON_PREFIX}_EXECUTABLE}" -c "import sys\ntry:\n   from distutils import sysconfig\n   sys.stdout.write(';'.join([sysconfig.get_python_lib(plat_specific=False,standard_lib=True),sysconfig.get_python_lib(plat_specific=True,standard_lib=True),sysconfig.get_python_lib(plat_specific=False,standard_lib=False),sysconfig.get_python_lib(plat_specific=True,standard_lib=False)]))\nexcept Exception:\n   import sysconfig\n   sys.stdout.write(';'.join([sysconfig.get_path('stdlib'),sysconfig.get_path('platstdlib'),sysconfig.get_path('purelib'),sysconfig.get_path('platlib')]))"
                         RESULT_VARIABLE _${_PYTHON_PREFIX}_RESULT
                         OUTPUT_VARIABLE _${_PYTHON_PREFIX}_LIBPATHS
                         ERROR_QUIET)