bug#43405: Tool bar item doesn't align to the right edge

[Eli Zaretskii]

> From: Robert Pluim <rpluim@gmail.com>
> Cc: 43405@debbugs.gnu.org,  juri@linkov.net
> Date: Thu, 17 Sep 2020 17:24:55 +0200
> 
> You know this is 2020, so truth == lies, and lies == truth, right?

Yes, I tend to forget this from time to time...

> So, once I actually follow the documentation and pass 'false' in the right
> place, the toolbar looks correct :-)

Great, thanks.

> Now the question is: do we want to expose this to lisp

I think so, yes.

> and if so, how?

Some attribute of the binding, similar to :image and :vert-only, I
guess?

> I mean, I have no idea if the macOS or MS-Windows tool bar have a
> similar feature.

I don't know about macOS, but MS-Windows uses the native tool bar
produced by our own code, i.e. it displays a Lisp string in a special
window.