Fixes#1280, tray icons not drawing background. This is a magic pattern only
usable for gdk_window_set_background_pattern() that sets the underlying
X window's background to ParentRelative.
The g_print documentation explicitly says not to do this, since
g_print is meant to be redirected by applications. Instead use
g_message for logging that can be triggered via GTK_DEBUG.
GtkStatusIcon is using a problematic, XEmbed-based protocol under X,
and we want to get rid of it eventually. Document our intentions by
marking GtkStatusIcon as deprecated.
https://bugzilla.gnome.org/show_bug.cgi?id=734826
