bug#47234: 28.0.50; frame-inner-height fails without window system on tab-bar-height

[Juri Linkov]

>>> Is the following close to TRT?
>>
>> If it produces the right result under all of the complications you
>> mentioned, sure.
>
> Thanks, it does AFAICT.  Hopefully Juri can confirm/deny for certain.
> (For example, I don't know when one would pick Ftab_bar_height over the
> frame property tab-bar-lines - maybe the latter can be used
> unconditionally?)

I agree with Martin that `tab-bar-height' should return a meaningful value
on --without-x builds too.

Please note this should be fixed on the release branch in Emacs 27.2
because the change in commit 6c5ddf0e0b was recently made in emacs-27.

I wonder why only tab-bar-height was added to frame-inner-height,
why not menu-bar-height as well?  Moreover, such function as
menu-bar-height doesn't exist at all.  Why only tab-bar-height is needed?