try some workarounds

Author: dunglas

.github/workflows/docker.yaml

@@ -197,7 +197,7 @@ jobs:
         run: |
           docker run --platform=${{ matrix.platform }} --rm \
             "$(jq -r '."builder-${{ matrix.variant }}"."containerimage.config.digest"' <<< "${METADATA}")" \
-            sh -c 'CGO_CFLAGS="-D_GNU_SOURCE" go test -tags ${{ matrix.race }} -v ./... && cd caddy && go test -tags nobadger,nomysql,nopgx ${{ matrix.race }} -v ./...'
+            sh -c 'CGO_CFLAGS="${CGO_CFLAGS}" go test -tags ${{ matrix.race }} -v ./... && cd caddy && go test -tags nobadger,nomysql,nopgx ${{ matrix.race }} -v ./...'
         env:
           METADATA: ${{ steps.build.outputs.metadata }}
   # Adapted from https://docs.docker.com/build/ci/github-actions/multi-platform/

.github/workflows/tests.yaml

@@ -54,7 +54,7 @@ jobs:
         working-directory: internal/testcli/
         run: go build
       - name: Run library tests
-        run: CGO_CFLAGS="-D_GNU_SOURCE" go test -race -v ./...
+        run: CGO_CFLAGS="${CGO_CFLAGS}" go test -race -v ./...
       - name: Run Caddy module tests
         working-directory: caddy/
         run: go test -tags nobadger,nomysql,nopgx -race -v ./...