bug#19576: write-file writes the wrong buffer

[martin rudalics]

> That'[s why I think we should do this on master, to see if this causes
> any problems.

It shouldn't because, as Anders remarked, it already worked this way in
Emacs 23.  So I tend to install this on Emacs-25.

>>   > The documentation
>>   > seems to suggest that both of them should be run in this situation.
>>
>> ‘window-configuration-change-hook’ shouldn't run since the window
>> configuration does not change.
>
> But the ELisp manual says it should:
>
>     -- Variable: window-configuration-change-hook
>         A normal hook that is run every time you change the window
>         configuration of an existing frame.  This includes splitting or
>         deleting windows, changing the sizes of windows, or displaying a
>                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>         different buffer in a window.

Taken literally we'd then have to run ‘window-configuration-change-hook’
also when we resize windows without resizing the frame.  In particular,
we'd then have to run it in prepare_menu_bars and in redisplay_internal.
Do we really want to do that?  If so, we could easily obsolete
‘window-size-change-functions’ because then every case would have been
already covered by ‘window-configuration-change-hook’ before.

martin