On Sun, Feb 21, 2016 at 2:46 AM, Ulrich Mueller <ulm@gentoo.org> wrote:
>>>>>> On Sat, 20 Feb 2016, Jim Meyering wrote:
>
>> I have fixed the regex-oriented problem with the attached patch [...]
>
> I confirm that this patch (applied to sys-apps/grep-2.23 in Gentoo)
> fixes the problem for me.

Thanks for checking.
I reread the patch I pushed and was dismayed to see I'd left
in a debugging statement.  This additional patch removes
the offending line (harmless unless you have a writable
directory named /t):