bug#64451: 30.0.50; split-root-window-right ignores side windows

[Eli Zaretskii]

Ping!  Hugo, could you please take a look?

> Cc: 64451@debbugs.gnu.org, aaronjensen@gmail.com
> Date: Sat, 08 Jul 2023 12:09:32 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> 
> > Date: Fri, 7 Jul 2023 15:57:12 +0200
> > Cc: 64451@debbugs.gnu.org
> > From: martin rudalics <rudalics@gmx.at>
> > 
> > There are two bugs.  The first one is that splitting a root window with
> > side windows is always an error unless a new side window on another side
> > should be made.  This should be fixed by the attached patch.
> > 
> > The second bug is that the 'split-root-window-...' functions probably
> > should split 'window-main-window' on that frame instead.  I'd rather
> > leave the fix for that to the people who wrote those functions.
> 
> Hugo, I guess this means you?  Could you please look into this issue?
> 
> Thanks.