The windows we create use a simple pattern as content, as that's
easier to follow than completely empty windows. GTK4 no longer
allows hooking into the drawing of arbitrary widgets, so prepare
for that by using a dedicated subclass instead of a signal handler.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2733>
Drawing windows got a lot more involved with the advent of client-side
decorations. Instead of accounting for visible and invisible borders,
titlebar and shadows when necessary, just add an empty child for the
custom drawing.
https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/887
Add an option for windows created with Scripting.createTestWindow()
to continually redraw themselves; this is for testing performance
of application updates.
https://bugzilla.gnome.org/show_bug.cgi?id=732350
The switch to GNOME_COMPILE_WARNINGS() caused -Wall and other
warnings to not actually be used since GNOME_COMPILE_WARNINGS()
just sets WARN_CFLAGS. Add WARN_CFLAGS to AM_CFLAGS so that
it takes effect.
Add -Wno-error=deprecated-declarations so that when -Werror is
enabled, we don't fail on all the deprecated cogl and clutter
symbols.
https://bugzilla.gnome.org/show_bug.cgi?id=730408
