Subject: grep -F: fix a heap buffer (read) overrun

From: Jim Meyering <[email-masked]>
Date: Sat, 10 Jan 2015 15:43:02 -0800

Colleagues Nima Aghdaii and Yuliy Pisetsky found and fixed a heap
buffer overrun in grep's kwset.c.  The underlying bug, already hard to
trigger, would most often result in a "mere" heap UMR (uninitialized
memory read), but Yuliy constructed inputs (see the new test) that
cause a buffer overrun.

I'm attaching two other related patches:
  - grep: avoid false-positive UMR
  - tests: add support for ASAN memory poisoning

I expect to push these by Monday.