Use distutils provided by setuptools

The distutils module provided by the stdlib has been deprecated in
Python 3.10. This PR sets an env var that is read by setuptools which
will shim its vendored copy of distutils if present avoiding a failure
once distutils is removed from the stdlib.

Signed-off-by: Jordan Borean <jborean93@gmail.com>

setup.py

@@ -1,10 +1,6 @@
 #!/usr/bin/env python
 from __future__ import print_function
 
-from setuptools import setup
-from setuptools import Distribution
-from setuptools.command.sdist import sdist
-from setuptools.extension import Extension
 import subprocess
 import platform
 import re
@@ -13,6 +9,17 @@
 import shutil
 import shlex
 
+# Enables the vendored distutils in setuptools over the stdlib one to avoid
+# the deprecation warning. Must be done before importing setuptools,
+# setuptools also must be imported before distutils.
+# https://github.com/pypa/setuptools/blob/main/docs/deprecated/distutils-legacy.rst
+os.environ['SETUPTOOLS_USE_DISTUTILS'] = 'local'
+
+from setuptools import setup  # noqa: E402
+from setuptools import Distribution  # noqa: E402
+from setuptools.command.sdist import sdist  # noqa: E402
+from setuptools.extension import Extension  # noqa: E402
+
 
 SKIP_CYTHON_FILE = '__dont_use_cython__.txt'