Revert "Try to resolve build failures by switching back to CPython's distutils...

Revert "Try to resolve build failures by switching back to CPython's distutils instead of using the one in setuptools 0.60."

This reverts commit 0ec33692.

.github/workflows/ci.yml

@@ -191,9 +191,6 @@ jobs:
       BACKEND: ${{ matrix.backend }}
       OS_NAME: ${{ matrix.os }}
       PYTHON_VERSION: ${{ matrix.python-version }}
-      # Use CPython's distutils instead of setuptools's copy.
-      # See https://github.com/pypa/setuptools/pull/2896
-      SETUPTOOLS_USE_DISTUTILS: local
       GCC_VERSION: 8
       USE_CCACHE: 1
       CCACHE_SLOPPINESS: "pch_defines,time_macros"

Makefile

@@ -90,7 +90,6 @@ wheel_%: dist/$(PACKAGENAME)-$(VERSION).tar.gz
 		-e CFLAGS="$(MANYLINUX_CFLAGS)" \
 		-e LDFLAGS="$(MANYLINUX_LDFLAGS) -fPIC" \
 		-e WHEELHOUSE=wheelhouse$(subst wheel_musllinux,,$(subst wheel_manylinux,,$@)) \
-	    -e SETUPTOOLS_USE_DISTUTILS=local \
 		quay.io/pypa/$(subst wheel_,,$@) \
 		bash -c '\
 			rm -fr /opt/python/*pypy* ; \