build: enable `--error-on-warn` for POSIX workflows

Treat warnings as errors for non-deps code on Linux and macOS workflows.

Signed-off-by: Richard Lau <riclau@uk.ibm.com>

PR-URL: https://github.com/nodejs/node/pull/33357
Refs: https://github.com/nodejs/node/pull/32685
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>

.github/workflows/test-linux.yml

@@ -18,6 +18,6 @@ jobs:
       - name: Environment Information
         run: npx envinfo
       - name: Build
-        run: make build-ci -j2 V=1
+        run: make build-ci -j2 V=1 CONFIG_FLAGS="--error-on-warn"
       - name: Test
         run: make run-ci -j2 V=1 TEST_CI_ARGS="-p dots"

.github/workflows/test-macos.yml

@@ -18,6 +18,6 @@ jobs:
       - name: Environment Information
         run: npx envinfo
       - name: Build
-        run: make build-ci -j8 V=1
+        run: make build-ci -j8 V=1 CONFIG_FLAGS="--error-on-warn"
       - name: Test
         run: make run-ci -j8 V=1 TEST_CI_ARGS="-p dots"