Make meson link libmutter using -fvisibility=hidden, and introduce META_EXPORT
and META_EXPORT_TEST defines to mark a symbols as visible.
The TEST version is meant to be used to flag symbols that are only used
internally by mutter tests, but that should not be considered public API.
This allows us to be more precise in selecting what is exported and what is
not, without the need of a version-script file that would be more complicated
to maintain.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/395
This is used to request key focus on the close dialog whenever
a window that is frozen would receive key focus. Also, ensure
that the dialog gets focus when first shown if the window was
meant to receive input.
https://bugzilla.gnome.org/show_bug.cgi?id=762083
This is an interface that can be used to implement the "application
is not responding" dialog. One instance is created per window, which
is initially hidden, and can be shown/hidden on demand.
https://bugzilla.gnome.org/show_bug.cgi?id=711619
