bug#57949: git head; unportable test(1) operator

[Eli Zaretskii]

> Date: Tue, 20 Sep 2022 11:54:55 +0000
> From: Gregory Heytings <gregory@heytings.org>
> cc: 57949@debbugs.gnu.org
> 
> 
> >>> Makefile.in started using "==" as test(1) comparison operator.
> >>>
> >>> This is not portable, only bash supports it. POSIX mandates "=".
> >>
> >> Thanks, fixed!
> >
> > Gregory, why are there ZERO-WIDTH SPACE characters in the top-level 
> > Makefile.in?  What purpose do they server, and why cannot we do the same 
> > with ASCII characters?
> >
> 
> Their purpose is to make the text behave exactly like the "CC", "ELC", 
> "GEN", "INFO", ... messages printed by make.

I don't think I understand -- what do you expect to happen, as
opposed to when these are removed?

> If it's problematic to have zero-width space characters there, they
> could be removed and/or replaced by something else.

Depending on how you view them, they could appear as "<U+200B>", in
inverse video, on a terminal's display.  Which stands out and gets in
the way of reading.