Explicitly declare the usage of distutils from Python stdlib for tests

setuptools 60+ bundles distutils which then have an impact on the test
environment, causing test_with_pip to fail.
Resolves: https://bugzilla.redhat.com/2064734

python3.9.spec

@@ -17,7 +17,7 @@ URL: https://www.python.org/
 #global prerel ...
 %global upstream_version %{general_version}%{?prerel}
 Version: %{general_version}%{?prerel:~%{prerel}}
-Release: 2%{?dist}
+Release: 3%{?dist}
 License: Python
 
 
@@ -1198,6 +1198,11 @@ done
 
 %check
 
+# setuptools 60+ uses its own copy of distutils by default
+# this setting must be overriden with the environment variable for
+# Python tests to use the standard library's distutils
+export SETUPTOOLS_USE_DISTUTILS=stdlib
+
 # first of all, check timestamps of bytecode files
 find %{buildroot} -type f -a -name "*.py" -print0 | \
     LD_LIBRARY_PATH="%{buildroot}%{dynload_dir}/:%{buildroot}%{_libdir}" \
@@ -1800,6 +1805,10 @@ CheckPython optimized
 # ======================================================
 
 %changelog
+* Wed Mar 16 2022 Karolina Surma <ksurma@redhat.com> - 3.9.10-3
+- Fix the test suite support for setuptools >= 60
+Resolves: rhbz#2064734
+
 * Fri Jan 21 2022 Fedora Release Engineering <releng@fedoraproject.org> - 3.9.10-2
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_36_Mass_Rebuild