grep-3.11 regression on large directories

Hi!

Hanno B=C3=B6ck brought to my attention that grep-3.11 has a regression
on large directories.

This was fixed a year ago but hasn't yet propagated into a release.

(Maybe everyone else had already found out about this, but I didn't know
until now, so hopefully this helps someone else too.)

Bug: https://bugs.debian.org/1041588
Bug: https://debbugs.gnu.org/64773
Bug: https://bugs.gentoo.org/930825
Patch: https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=3Dd4d8abb39e=
b02c555f062b1f83ffcfac999c582f

thanks,
sam