ATK dependency added to GTK+

[Owen Taylor <otaylor redhat com>]

I've gone ahead and applied the patch to GTK+ to add a dependency
on the ATK library for accessibility support.

So, when building from CVS, you'll have to checkout, build and install
ATK after pango and before GTK+. (atk module in CVS)

This doesn't meant that there are no issues left to discuss about ATK,
though it is, hopefully getting close. And, in fact, one of the big
reasons for getting it into general circulation at this point is
so that as many people can comment on the APIs as possible.

I know the extra dependency and extra compile step is annoying;
before we ship I'd like to do one of:

 - Ship ATK as subdirectory of the GTK+ tarball.

 - Provide a single gtk+-everything (glib/pango/atk/pango) with
   a top level configure and Makefile.

But it is an independent module for now for maximal flexibility and to
make it clear that it could, in theory, be used with a application
that didn't use GTK+.

Regards,
                                        Owen