Disable build isolation for cibuildwheel

Author: abravalheri

.github/workflows/ci.yml

@@ -362,9 +362,13 @@ jobs:
       - uses: pypa/[email protected]
         env:
           CIBW_BUILD: cp39-*
-          CIBW_BEFORE_BUILD: pip install -e .
+          CIBW_BEFORE_BUILD: pip install -U pip>=23.2.1 setuptools>=68.0.0 wheel>=0.41.1 -e .
           CIBW_ARCHS_MACOS: "x86_64 universal2 arm64"
           CIBW_BUILD_VERBOSITY: 1
+          CIBW_BUILD_FRONTEND: pip  # pip allows disabling isolation via env var
+          CIBW_ENVIRONMENT: PIP_NO_BUILD_ISOLATION=false
+          # ^ -- necessary to use working copy of setuptools-rust,
+          #      (however PIP_NO_BUILD_ISOLATION is counter-intuitive: see pypa/pip#5735)
         with:
           package-dir: examples/namespace_package