ci: Explicitly specify job dependencies

We can speed up CI a bit by allowing build jobs to run in parallel
with review jobs, and don't have test jobs wait for non-default
build configuration builds.

See https://gitlab.gnome.org/help/ci/yaml/README.md#needs for details.

https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1398

.gitlab-ci.yml

@@ -17,6 +17,7 @@ check-commit-log:
 
 build-mutter:
   stage: build
+  needs: []
   script:
     - meson . build -Dbuildtype=debugoptimized -Db_coverage=true -Degl_device=true -Dwayland_eglstream=true --werror --prefix /usr
     - ninja -C build
@@ -31,6 +32,7 @@ build-mutter:
 
 build-without-opengl-and-glx:
   stage: build
+  needs: []
   script:
     - meson . build -Dbuildtype=debugoptimized -Dopengl=false -Dglx=false -Degl_device=true -Dwayland_eglstream=true --werror --prefix /usr
     - ninja -C build
@@ -44,6 +46,7 @@ build-without-opengl-and-glx:
 
 build-without-native-backend-and-wayland:
   stage: build
+  needs: []
   script:
     - meson . build -Dbuildtype=debugoptimized -Dnative_backend=false -Dudev=false -Dwayland=false -Dcore_tests=false --werror --prefix /usr
     - ninja -C build
@@ -59,6 +62,7 @@ test-mutter:
   stage: test
   dependencies:
     - build-mutter
+  needs: ["build-mutter"]
   variables:
     XDG_RUNTIME_DIR: "$CI_PROJECT_DIR/runtime-dir"
     GSETTINGS_SCHEMA_DIR: "$CI_PROJECT_DIR/build/data"
@@ -84,6 +88,7 @@ test-mutter-coverage:
   stage: coverage
   dependencies:
     - test-mutter
+  needs: ["test-mutter"]
   script:
     - ninja -C build coverage
     - cat build/meson-logs/coverage.txt
@@ -100,6 +105,7 @@ can-build-gnome-shell:
   stage: test
   dependencies:
     - build-mutter
+  needs: ["build-mutter"]
   before_script:
     - meson install --no-rebuild -C build
   script: