BUG: Fix python3.12 distutils dev.py build

Fix gh-18689 gh-18922

python3.12 removes distutils and scipy dev.py uses
distutils for the meson based build in debian python.
With python3.12 debian has patched sysconfig and no
longer requires dependence on distutils.

dev.py

@@ -111,14 +111,6 @@ def task_meta(cls, **kwargs):
 import traceback
 from concurrent.futures.process import _MAX_WINDOWS_WORKERS
 
-# distutils is required to infer meson install path
-# if this needs to be replaced for Python 3.12 support and there's no
-# stdlib alternative, use CmdAction and the hack discussed in gh-16058
-with warnings.catch_warnings():
-    warnings.filterwarnings("ignore", category=DeprecationWarning)
-    from distutils import dist
-    from distutils.command.install import INSTALL_SCHEMES
-
 from pathlib import Path
 from collections import namedtuple
 from types import ModuleType as new_module
@@ -337,14 +329,22 @@ def get_site_packages(self):
         Depending on whether we have debian python or not,
         return dist_packages path or site_packages path.
         """
-        if 'deb_system' in INSTALL_SCHEMES:
-            # debian patched python in use
-            install_cmd = dist.Distribution().get_command_obj('install')
-            install_cmd.select_scheme('deb_system')
-            install_cmd.finalize_options()
-            plat_path = Path(install_cmd.install_platlib)
-        else:
+        if sys.version_info >= (3, 12):
             plat_path = Path(get_path('platlib'))
+        else:
+            # distutils is required to infer meson install path
+            # for python < 3.12 in debian patched python
+            with warnings.catch_warnings():
+                warnings.filterwarnings("ignore", category=DeprecationWarning)
+                from distutils import dist
+                from distutils.command.install import INSTALL_SCHEMES
+            if 'deb_system' in INSTALL_SCHEMES:
+                # debian patched python in use
+                install_cmd = dist.Distribution().get_command_obj('install')
+                install_cmd.finalize_options()
+                plat_path = Path(install_cmd.install_platlib)
+            else:
+                plat_path = Path(get_path('platlib'))
         return self.installed / plat_path.relative_to(sys.exec_prefix)