bug#59620: 29.0.50; Wrong global-mode-string position in tab-bar + emacs -nw

[Juri Linkov]

>> Looks like tab-bar-format-align-right is evaluated with the wrong window
>> being the selected one: it should use the tab-bar pseudo-window to do what
>> you expect.
>
> I don't know what is the root cause, but it's a reasonable hypothesis.
> Not sure why it only affects "emacs -nw", though.
>
> Do you know how to get the tab-bar pseudo-window?  It seems that
> "f->tab_bar_window" it's not exposed from C to elisp.

Unless Eli can suggest how to fix `(space :align-to (- right (,hpos)))
to work on TTY frames the same way as it works on GUI frames,
I could try to rewrite it to avoid the keyword `right', i.e. to use
`(space :align-to (,hpos-from-left)) where hpos-from-left could be
calculated by using string-pixel-width on the text from the left side.