ci/unit-tests: enable dlopen note verification tests

Enable the `dlopen` unit test suite in GitHub Actions, except for the
following configurations where linker garbage collection (`--gc-sections`)
or dead-code elimination fails to drop unused dlopen symbols:

- ppc64le (both GCC and Clang)
- s390x (GCC only)
- Sanitizer-enabled setups

.github/workflows/unit-tests.sh

@@ -132,6 +132,12 @@ for phase in "${PHASES[@]}"; do
             ninja -C build -v
             # Ensure setting a timezone (like the reproducible build tests do) does not break time/date unit tests
             TZ=GMT+12 meson test "${MESON_TEST_ARGS[@]}" -C build --print-errorlogs --no-stdsplit --quiet
+
+            # Linker garbage collection for unused symbols appears to be broken on ppc64le (both GCC and CLANG) or s390x (GCC).
+            # Skip the dlopen note verification test in those specific configurations.
+            if ! [[ "$(uname -m)" == "ppc64le" || ( "$(uname -m)" == "s390x" && "$phase" == "RUN_GCC" ) ]]; then
+                meson test -C build --suite=dlopen --print-errorlogs --no-stdsplit --quiet
+            fi
             ;;
         RUN_ASAN_UBSAN|RUN_GCC_ASAN_UBSAN|RUN_CLANG_ASAN_UBSAN|RUN_CLANG_ASAN_UBSAN_NO_DEPS)
             # TODO: drop after we switch to ubuntu 26.04

.github/workflows/unit-tests.yml

@@ -99,3 +99,6 @@ jobs:
 
       - name: Test
         run: mkosi box -- meson test -C build --print-errorlogs --no-stdsplit --quiet
+
+      - name: Test (dlopen)
+        run: mkosi box -- meson test -C build --print-errorlogs --no-stdsplit --quiet --suite=dlopen