Avoid importing from setuptools._distutils (#16348)

Fixes #16318, as requested by setuptools maintainer

mypyc/build.py

@@ -40,31 +40,28 @@
 from mypyc.namegen import exported_name
 from mypyc.options import CompilerOptions
 
-if sys.version_info < (3, 12):
- if TYPE_CHECKING:
+try:
+ # Import setuptools so that it monkey-patch overrides distutils
+ import setuptools
+except ImportError:
+ pass
+
+if TYPE_CHECKING:
+ if sys.version_info >= (3, 12):
+ from setuptools import Extension
+ else:
  from distutils.core import Extension as _distutils_Extension
  from typing_extensions import TypeAlias
 
  from setuptools import Extension as _setuptools_Extension
 
  Extension: TypeAlias = Union[_setuptools_Extension, _distutils_Extension]
 
- try:
- # Import setuptools so that it monkey-patch overrides distutils
- import setuptools
- except ImportError:
- pass
- from distutils import ccompiler, sysconfig
+if sys.version_info >= (3, 12):
+ # From setuptools' monkeypatch
+ from distutils import ccompiler, sysconfig # type: ignore[import-not-found]
 else:
- import setuptools
- from setuptools import Extension
- from setuptools._distutils import (
- ccompiler as _ccompiler, # type: ignore[attr-defined]
- sysconfig as _sysconfig, # type: ignore[attr-defined]
- )
-
- ccompiler = _ccompiler
- sysconfig = _sysconfig
+ from distutils import ccompiler, sysconfig
 
 
 def get_extension() -> type[Extension]: