GTK+ deprecations

[Matthias Clasen <matthias clasen gmail com>]

Just a heads-up:

now that GTK+ 3 is out, we are picking up our regular api maintenance
again, and started deprecating apis that will be going away in GTK+ 4.
The most prominent newcomers among the deprecated apis in GTK+ 3.1.6
are all the h/v subclasses:

GtkHBox GtkVBox
GtkHScale GtkVScale
GtkHScrollbar GtkVScrollbar
GtkHSeparator GtkVSeparator
GtkHButtonBox GtkVButtonBox
GtkHPaned GtkVPaned

Of these, hboxes and vboxes are probably the most abundant. I'd
encourage everybody to do the trivial 1-line conversion from GtkH/VBox
to GtkBox, but for todays release, it may be more practical to just
make sure that -UGTK_DISABLE_DEPRECATED ends up in your cflags.


Matthias