[3.24] Annotate sequence argument of GtkGesture signals as nullable

See merge request !2521

searchengine: Prepare for apps linking to Tracker 2.x

See merge request !2513

Given it does seem likely Tracker is going to miss the goal to get all
applications ported to Tracker 3, the scenario where there's applications
linking to Tracker 2.x while GTK was built with Tracker 3 support becomes
more likely.

Avoid the upcoming GType clashes if that were the case, and resort to the
good (I lie) old Tracker 2 search engine.

gdk: Keep a reference on the last source device

See merge request !2510

This device may go away, which means we have a pointer to a possibly
stale object. Keep a reference here, and let future events bring this
accounting up-to-date when the mouse pointer is next updated via other
device.

Fixes: #855

Fix resource leak in gdk_display_close() under Wayland

See merge request !2508

When using the gdk_display_close(), the handle to the Wayland compositor was not released.
This could cause the consumption of all available handles, preventing other processes from accessing the display.

Fixing this by calling wl_display_disconnect() when releasing the GdkWaylandDisplay object.

Signed-off-by: Julien Ropé <jrope@redhat.com>

wayland: Fix dnd hotspot movement

See merge request !2491

Look up font and mouse settings in gsettings-desktop-schemas (3.24)

See merge request !2490

_gdk_wayland_window_offset_next_wl_buffer() moves the window relatively to
its current position, pass it a delta instead of new position.

Handle both these settings, and the older settings-daemon ones for
backwards compatibility. The keys are already checked for existence
in the schema, so it will just use the existing ones.

Prefer this location, but also look for the old location in
settings-daemon for backwards compatibility. This applies to both
direct settings lookups and via the settings portal.

CUPS uses resource paths in the form of "printers/printer_name"
or "classes/class_name" so it is enough to remove the "printers/"
or "classes/" prefix and use the string behind it as a name.

There was recently introduced a wrong check for the prefix.
This commit fixes it in the way it was originally intended.

Adwaita: error labels insensitive & backdrop states

See merge request !2451

# Conflicts:
#   gtk/theme/Adwaita/_common.scss
#   gtk/theme/Adwaita/gtk-contained-dark.css
#   gtk/theme/Adwaita/gtk-contained.css

- address colored labels for the two states

See #3063 (comment 891618)

Adwaita: error labels insensitive & backdrop states

See merge request !2448

- address colored labels for the two states

See #3063 (comment 891618)

Adwaita: error labels and entries

See merge request !2441