bug#49978: 28.0.50; grep-highlight-matches auto-detection broken on macOS [PATCH]

[Eli Zaretskii]

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Tue, 10 Aug 2021 14:54:43 +0200
> 
> The auto-detection of colourised grep fails on macOS (and presumably BSD in 
> general) because grep --help exits with a nonzero status (while still 
> printing a useful option summary).
> 
> We should just ignore the exit status. Anyone against the attached patch?

Not me (this time ;-).  Although perhaps we should strengthen the
search string to be sure we don't hit some false positive: "--color"
sounds a bit too general, no?  Or do you think it's good enough even
if "--help" causes a non-zero exit code?