Eli Zaretskii wrote:

> I like it because it is future proof, and makes our burden of
> remembering this issue easier.
> 
> Thanks.

You're welcome. Stefan privately emailed me some helpful comments that improved 
the patch (thanks!), and I installed the attached into master. In the hope that 
this has laid Bug#20202 to rest (at least on modern GNU systems running Bash 4.4 
or later), I'm boldly closing the bug report.