ci: add a build job for the various session managers we build

We allow those jobs to fail so a theoretical issue in the session
managers doesn't prevent our pipeline from completing.
The failure could however be due to our integration of the session
managers, so failures should still be inspected nonetheless.

.gitlab-ci.yml

@@ -234,6 +234,21 @@ build_release:
     matrix:
       - CC: [gcc, clang]
 
+build_session_managers:
+  extends:
+    - .build_on_fedora
+  script:
+    - echo "Building with meson options $MESON_OPTIONS"
+    - meson "$BUILD_DIR" . --prefix="$PREFIX" $MESON_OPTIONS
+    - ninja -C "$BUILD_DIR"
+    - ninja -C "$BUILD_DIR" install
+  variables:
+    MESON_OPTIONS: "-Dsession-managers=$SESSION_MANAGERS"
+  parallel:
+    matrix:
+      - SESSION_MANAGERS: ["[]", "wireplumber", "media-session", "media-session,wireplumber", "wireplumber,media-session" ]
+  allow_failure: true
+
 valgrind:
   extends:
     - .build_on_fedora