bug#11810: 24.1.50; `vc-diff' shrinks pre-existing window

[martin rudalics]

> Commands messing up existing window configuration is one of my top
> Emacs annoyances, and AFAIK it confuses the new users, too.
> Maybe nil check for (window-prev-buffers) should be instead included in
> `shrink-window-if-larger-than-buffer', with a way to override it?

This problem has been previously discussed here

http://lists.gnu.org/archive/html/emacs-devel/2010-08/msg00638.html

If people want an option here, please decide on

- the values it should take, and

- how to meld it with `temp-buffer-resize-mode'.

martin