bug#21513: assertion error in pop_fail_stack

[Paul Eggert]

Paul Eggert wrote:
> It's a bug in the glibc regular expression matcher,
> and as such will need a glibc fix.  I plan to propose a patch there.

I created glibc bug report BZ#18986 about this, and put in a pointer to the 
Gnulib patch.  Hope that's enough to get it fixed in glibc, eventually.

https://sourceware.org/bugzilla/show_bug.cgi?id=18986