[mutter] (28 commits) Non-fast-forward update to branch wip/nielsdg/meta-plugin-derivable

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

The branch 'wip/nielsdg/meta-plugin-derivable' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  f47b627... MetaPlugin: use G_DECLARE_DERIVABLE_TYPE.

Commits added to the branch:

  19930c6... backends/stage: Remove MetaStagePrivate (*)
  9adf882... backends/stage: Remove unused function declaration (*)
  213ed80... backends: Move clutter frame clock freeze/thaw API to Clutt (*)
  25c53b2... backend: Freeze frame clock when headless (*)
  1dff74e... build: Fix libs and cflags in autotools .pc file (*)
  2a4f1be... clutter/actor: Don't forget va_end if using varargs (*)
  9fb46cc... clutter/keyframe-transition: Properly compare keys (*)
  0b9404d... clutter/device-manager/evdev: Fix constraint cb (*)
  fa49528... window: Really force update monitor on hot plugs (*)
  59acb38... clutter: Avoid redundant margin changes (*)
  9f79cf8... Revert "clutter: Avoid redundant margin changes" (*)
  9a12bef... Bump version to 3.31.2 (*)
  6c5baf8... keybindings: Limit corner move to current monitor (*)
  bda9c35... wayland/output: Rotate physical dimensions as well (*)
  626c374... clutter/master-clock: Destroy source when paused (*)
  5b3e439... cogl/tests: Increase the conform test timeout to 120 s (*)
  a892e7a... clutter/tests: Remove events-touch test (*)
  e2cd9ab... Dockerfile: Align comment with command (*)
  fe1d9fb... tests: Override Wayland display name in test_init() (*)
  bd624e4... tests: Override X11 display number (*)
  18c1d96... gitlab-ci: Add test stage (*)
  76760bf... tests: Make all alarm filters use the same type (*)
  1266c20... monitor-unit-tests: Also run a X11 client while testing (*)
  c8a4e37... tests/test-client: Add "resize" command (*)
  563c5b0... monitor-unit-tests: Try resizing clients while headless (*)
  787bb43... x11/window: Minor cleanup (*)
  740c229... build: Don't hardcode the path of python3 (*)
  fd03455... MetaPlugin: use G_DECLARE_DERIVABLE_TYPE.

(*) This commit already existed in another branch; no separate mail sent