bug#12067: 24.1; improper menu formatting with multiple \t chars

[Eli Zaretskii]

> From: "Drew Adams" <drew.adams@oracle.com>
> Cc: <12067@debbugs.gnu.org>
> Date: Sat, 28 Jul 2012 13:10:50 -0700
> 
> > If we care about this issue, we could perhaps expand TABs into the
> > appropriate number of spaces, before passing the menu items to the
> > toolkit.
> 
> I thought of that, but menu items are often realized using proportional fonts.
> 
> What is really needed, I guess, is the equivalent of `move-to-column'.

move-to-column won't help, as it doesn't take pixel width of each
character into account.