Merge branch 'jk/asan-build-fix' into maint

Work around test breakages caused by custom regex engine used in
libasan, when address sanitizer is used with more recent versions
of gcc and clang.

* jk/asan-build-fix:
  Makefile: use compat regex with SANITIZE=address

diff --cc Makefile
Simple merge

diff --cc compat/regex/regex.h
Simple merge