diff --git a/.github/workflows/test-cygwin.yml b/.github/workflows/test-cygwin.yml
index 9a1e46705de..e7ab6466e4e 100644
--- a/.github/workflows/test-cygwin.yml
+++ b/.github/workflows/test-cygwin.yml
@@ -104,7 +104,7 @@ jobs:
       - name: Build
         shell: bash.exe -eo pipefail -o igncr "{0}"
         run: |
-          SETUPTOOLS_USE_DISTUTILS=stdlib .ci/build.sh
+          .ci/build.sh
 
       - name: Test
         run: |
diff --git a/setup.py b/setup.py
index 0b6b0207764..7c1ad6dc5b2 100755
--- a/setup.py
+++ b/setup.py
@@ -515,6 +515,7 @@ def build_extensions(self):
 
         elif sys.platform == "cygwin":
             # pythonX.Y.dll.a is in the /usr/lib/pythonX.Y/config directory
+            self.compiler.shared_lib_extension = ".dll.a"
             _add_directory(
                 library_dirs,
                 os.path.join(