Allows easier debugging.

This was possible in muffin <= 5.2 but was mistakenly disallowed
in 5.4.

Zenity is used by the default force-quit, display-changes and
session-save dialogs. Cinnamon implements the first two, and the
last we don't support at this time, so this change won't have much
impact.

Fixes #666.  \m/

It was disabled pre-5.4, make it so once more.

don't call meta_monitor_spec_free() on a NULL pointer.

Backported from:
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1685

Fixes #668.

keybindings.

ref: linuxmint/cinnamon#11674

Fixes #664

finalize.

This is done in the dispose vfunc already so would be a no-op
anyhow, but throws warnings now in recent glib versions.

see:
linuxmint/cinnamon#11562,
https://gitlab.gnome.org/GNOME/mutter/-/issues/2566

closes: linuxmint/cinnamon#11562.

cinnamon again.

It got renamed, and notifies removed, in 5.4. The window-list
applet uses this to adjust title indicators.

These were part of MetaScreen, and are part of CinnamonScreen now,
but we want to move away from using that, so add these signals
back to MetaDisplay (where most of MetaScreen's functions went
already).

introspection.

when calculating the crtc scale based on Xft.dpi.

- cinnamon-settings-daemon retrieves the global scale from muffin,
  and the text scale from gsettings, calculates the dpi and sets
  it on the server.
- muffin retrieves the dpi from the server and calculates the global
  scale from that *rounding to the nearest integer*. A text factor
  of >= 1.5 causes a higher global scale to be assumed each time
  muffin restarts. Muffin triggers a dbus signal, and cinnamon-
  settings-daemon does its thing over again.

ref: linuxmint/mint21.1-beta#43

cover a new window.

This check occurs prior to placement (and plays a part in how
placement is calculated), but prior to placing the window, its
position and monitor aren't up-to-date. There are still a number
of things we can check, however, and it's better to be accurate
on what we do check rather than reporting false positives.

initial window focus and stacking to be wrong (mostly because of
bad timestamps), and correct them.

- a modal window with a parent that is the current input focus should
  never appear below that parent.
- a modal window spawned via portal (rather than 'native').

Flatpak apps, along with browsers (and electron apps) are now using
this portal mechanism to provide a dialog appropriate to the current
environment (such as Kde, Gtk). The dialogs aren't direct descendants
of their parent windows, their timestamps can/will be earlier than
the most recent user time for the parents, causing muffin to refuse
focus.

ref:
linuxmint/cinnamon#11368
linuxmint/cinnamon#10868

Both meta_window_maximize and meta_window_tile use
meta_window_maximize_internal(), and edge constraints are already
recalculated and updated there.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2579>

meta_window_tile gets called by the grabbed window's match(es) during
tile resizing. These incremental changes don't need to be animated.

upstream:
https://gitlab.gnome.org/GNOME/mutter/-/commit/559e6ff327a358a6daa4b0683fee95700591749f

This reverts and replaces commit a8068f3.

bottom_window_group is a child actor of the window_group, so the order
likely matters here.

It's too aggressive in its current state, but making it any less
so runs afoul of the fact that both server- and client-decorated
windows report inaccurate sizes during placement, as their
decorations and/or shadows haven't been accounted for.

* Bring back window placement-mode to allow pointer and manual window placement.

* Mark center-new-windows option as obsolete.