bug#68235: 29.1.90; Switching tabs stops following process output in selected window

[Juri Linkov]

>> One problem is that whether to run the hook is defined by the fourth 
>> argument.
>> This means that it a user needs to use the hook, there is no way to change
>> the fourth argument of the existing function calls in core commands.
>>
>> Maybe better to keep windows when the hook is not empty?
>> I.e. something like this for 'window--state-put-2':
>>
>>    (when window-state-put-keep-window-functions
>>      ...
>>      (push (list window old-buffer-or-name start-pos point-pos)
>>            window-state-put-kept-windows))
>
> You mean to do away with the KEEP-WINDOWS argument and keep windows iff
> `window-state-put-keep-window-functions' is non-nil?

Yes, I meant removing the KEEP-WINDOWS argument.

> This would be up to you to decide.  Only some practice can tell what's
> better here.

Otherwise users won't be able to use this hook for existing commands
that don't set the KEEP-WINDOWS argument.