[mutter] (21 commits) Non-fast-forward update to branch bilelmoussaoui/x11-build-guards

[Bilal Elmoussaoui <bilelmoussaoui src gnome org>]

The branch 'bilelmoussaoui/x11-build-guards' 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:

  63e99be... compositor: Guard X11 types
  00ac796... core/display: Guard X11 types
  5fe725f... compositor/dnd: Guard X11 types

Commits added to the branch:

  b9a5f9a... backend: Make get_cogl_context introspectable (*)
  d7c0ecc... cogl/pipeline: Make Snippet API introspectable (*)
  2fd6372... cogl/snippet: Make API introspectable (*)
  86d3a6b... cogl/snippet: Use "Returns:" for introspection annotations (*)
  9930b5d... x11/selection: Unset selection ownership on shutdown (*)
  c575696... tests/test-client: Add clipboard-set command (*)
  e103395... wayland: Add getter for XWayland manager object (*)
  bdb3440... xwayland: Only warn on X IO errors when X11 is mandatory (*)
  c9e7cf4... xwayland: Add API to send signal to the Xwayland process (*)
  6c0a917... selection: Return an error if trying to transfer from NULL  (*)
  82d9ef7... x11/input-selection-stream: Handle Xwayland going away (*)
  7e8bddc... tests/async-waiter: Keep track of X11 display it was create (*)
  e939d5b... tests: Check that X11 selections handle Xwayland disappeari (*)
  83ed7b7... xwayland: Remove stray newline (*)
  1cf2940... build: Bump API version (*)
  8186022... restart: Don't pass error as unused user data (*)
  f772b4c... restart: Make API that needs context take a context (*)
  efd6eec... compositor: Guard X11 types
  7873443... core/display: Guard X11 types
  17c4f97... compositor/dnd: Guard X11 types
  f188623... core/events: Guard X11 types

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