Adwaita: infobar borders

See merge request !962

build: fix --enable-profiler=no

See merge request !961

This fixes the --enable-profiler=no or --disable-profiler option.

Fixes #1965

- defined a bottom border for infobars, move styling into descendant box
  to hide border when unrevealed

Fixes #1165

build: always use utf-8 when reading/writing text files

See merge request !953

open() in text mode should never be used without an encoding because it defaults
to the locale encoding which is rarely what is wanted.

This fixes the Windows build in some cases (depending on the locale/paths used)

Require Harfbuzz only for Wayland and X11 backends.

See merge request !955

Do not add empty strings to GtkFileFilter

See merge request !957

When parsing a UI description for GtkFileFilter we should avoid passing
empty strings, to avoid issues when serialising the filter before
sending it over DBus.

Fixes: #1973

Be prepared for the eventuality that somebody
might reinsert the same action group without
holding any extra references on it.

This was observed as causing crashes in
gnome-builder.

This is reproducing a crash that was seen
in gnome-builder.

Closes: #1685

Closes: #1686

Closes: #1687

Otherwise the native window gets created with GDK_TYPE_HINT_NORMAL
and in fullscreen appears on its own screen or tab instead of over
the combo like it's supposed to.

Fixes #1968

Overlay: small improvements to documentation

See merge request !932

Report the monitor's connector name under Wayland

See merge request !951

Like we do on Wayland.

In this case, we copy it from the same source as the output name,
because it's going to match.

The xdg_output interface has a `name` property that reflects the output
name coming from the compositor.

This is the closest thing we can get to a connector name.

Fixes: #1961

The documentation for get_monitor_plug_name() says that we're returning
the name of the connector for the monitor, but we switched it to using
the model name.

The migration from GdkScreen's monitor API to GdkMonitor left out a way
to get the connector's name of a monitor. While there's no real
guarantee that the connector's name is stable, some system components
used it to uniquely identify a monitor until the next plug in/out event.

Since GTK 3 is API stable, we can only add a private setter and getter
functions pair, without a property.

We named the argument `position` in the code and doc arguments, but the
rest of the documentation referred to `index` instead. That was maybe
meant to hint at the child property named :index, but we can simply be
fully clear here. We can call the argument `index_`, replacing the local
variable with that name, thus avoiding any possible confusion with the
unrelated ::get-child-position, and refer users to :index for completion

`index_` is used instead of plain `index` in case anyone is #including
<strings.h> and getting the old index() function superseded by strchr();
see !932 (comment 531149)

Be a bit clearer about what :pass-through does, and point :index at the
corresponding reorder_overlay() method that explains what an index means

Some users expect that the Overlay will automatically request enough
size for its overlay children as well as its main child. It doesn't,
because it's just a GtkBin. Add a short paragraph pointing that out.

Close #1939

The only glancing mention of this we had was that GtkButton mentioned it
in passing when discussing how `button` could get contextual classes.

Fix action muxer parent chain

See merge request !950

Its the same we do on master. Until those tests
are reliable, it is better to not include them
and have a passing testsuite for ci.

Turns out g_strv_equal is recent.

Adwaita: few vars to adjust color & metrics

See merge request !947

The documentation for gtk_widget_get_action_group
and gtk_widget_list_prefixes states that both of
these operate on all the action groups that are
'available' to the widget.

Which means: they are meant to walk up the parent
muxer chain. So do that.

Add tests to verify the expected behavior.

Closes: #1396

andyholmes on IRC asked about this and it wasn't documented, so fix that