bug#32093: 27.0.50; M-x grep appends /dev/null to command line

[Eli Zaretskii <eliz@gnu.org>]

> From: Noam Postavsky <npostavs@gmail.com>
> Cc: 32093@debbugs.gnu.org,  dak@gnu.org,  michael.albinus@gmx.de
> Date: Mon, 09 Jul 2018 17:43:46 -0400
> 
> > But is there a good reason why we use HELLO for that?  Why not README,
> > say, whose first line will always start with "Copyright"?
> 
> I don't think there's a reason to use HELLO in particular.  etc/README
> doesn't have Copyright on the first line, but it does have COPYRIGHT at
> the beginning of a line (I think we do want something specifically in
> etc/, because we know `data-directory' tells us where to find it).

I meant the top-level README, which I think always will include a
Copyright line.

But that was just a suggestion.  I see Paul decided to continue using
etc/HELLO, just with a different search patterns.  If we are OK with
that, we can put that issue to rest.

There's still a broader issue of whether a test done with plain 'grep'
holds for any other "grep-like" program.  I'm not sure what to do with
that.

We could even take one more step back and ask ourselves why do we need
this particular test.  I believe it's because we want to support file
names with embedded newlines, in which case perhaps such niche use
cases could be supported by a special command or a special user
option?  I mean, it sounds strange to let a tail wag the dog, no?