Paul Eggert wrote:
> I plan to change GNU grep to use this new facility, and to add some grep test
> cases for this issue.

I did that by installing the attached patches into the grep master. This fixes 
the bug for me, so I'm closing the bug report.

These patches mostly just report the fix and add test cases. The actual fix was 
in gnulib, here:

http://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=b7bc3c1a4e78add4cbad39ae1a0c4fb0747b483f

This gnulib fix works around the underyling glibc facility which caused the 
problem, for which I've filed a bug report here:

https://sourceware.org/bugzilla/show_bug.cgi?id=19932

It's not clear when the glibc bug will be fixed. Until it is, one should expect 
similar problems to crop up in applications other than 'grep'.