Add app-menu button support in themes. This is done only to support
metacity theme format 3.5 version. Marco will not show this
button!

Based on metacity commit:
https://gitlab.gnome.org/GNOME/metacity/commit/6a2cc159

This was added only to add support for metacity theme format version 3.2.

Adapted from metacity for marco
origin commit: https://gitlab.gnome.org/GNOME/metacity/commit/d2b13461

Adapted from metacity for marco
Origin commit: https://gitlab.gnome.org/GNOME/metacity/commit/aab7b07a
Author:        Alberts Muktupāvels <alberts.muktupavels@gmail.com>
Date:          Fri Oct 3 19:57:08 2014 +0300

Origin: Ubuntu
Bug: https://bugzilla.gnome.org/show_bug.cgi
Bug-Ubuntu: https://bugs.launchpad.net/ubuntu/+source/metacity/+bug/506944
Author: Didier Roche <didrocks@ubuntu.com>

Add a new frame type META_FRAME_TYPE_ATTACHED which is used for
attached modal dialogs.

The theme format version is bumped to 3.2, and attached windows
can have borders defined in a metacity-theme-3.xml as:

 <window version=">= 3.2" type="attached" style_set="[name]"/>

If no style is defined for "attached", drawing will fall back
to the "border" type.

https://bugzilla.gnome.org/show_bug.cgi?id=592382

NOTE: Patch copied from mutter and adapted for metacity.

Add a preference /apps/mutter/general/attach_modal_dialogs. When
true, instead of having independent titlebars, modal dialogs appear
attached to the titlebar of the parent window and are moved
together with the parent window.

https://bugzilla.gnome.org/show_bug.cgi?id=612726

NOTE: Patch copied from mutter and adapted for metacity.

NOTE: Patch copied from mutter and adapted for metacity.