bug#22660: [PATCH] Implement horizontal scroll-bars in NS port

[martin rudalics]

> My attempt at enabling horizontal scroll-bars in the NS port. This
> patch also removes the custom NS scroll-bar handlers in favour of the
> standard ones. I think this *may* cause behaviour of the vertical
> scroll-bars to change slightly.
>
> I've tried to clean up some of the code as there were a few places
> where it didn't make a whole lot of sense to me. I guess that's due to
> the code I started with being a partial implementation.

Thank you.  With the limited testing capabilities of GNUStep it seems to
work.  Or better: If everything in the GNUStep worked as well as your
patch, the GNUStep port might even become usable one day ;-)

There is one aspect which might be part of the design but appears
nevertheless distracting for somone working mainly on other platforms:
When the entire buffer is visible, no sliders/rulers are shown.  Now,
some people want that in this case the scrollbar area(s) get removed
completely.  Personally, I'd prefer the sliders/ruler cover the entire
scroll bar area with the arrows possibly removed.  But maybe the current
behavior (which is so here ever since for the vertical case) is standard
on NS so don't let my remarks distract you.

Personally, I'd vote for including this in Emacs-25.  It's a completely
self-confined, local patch and we could avoid answering questions like
"why don't these work on Macs" after the forthcoming release.

In any case, many thanks for the accomplishment, martin