glibc strstr regression

[Eric Blake]

Urgh: https://sourceware.org/ml/libc-alpha/2018-09/msg00152.html says 
glibc has releases with a broken strstr, and I don't think gnulib's 
module is catching this particular bug.  At the same time, we may want 
to sync some of glibc's enhancements to strstr back into gnulib (my 
original coding of the two-way algorithm code landed in gnulib first, 
then was copied to glibc; glibc has since made improvements to it).

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org