Re: [PATCH 1/2] tests: fix unportable "\?" and "\+" regex syntax

Ævar Arnfjörð Bjarmason  [off-list ref] writes:

Fix widely supported but non-POSIX basic regex syntax introduced in
[1] and [2]. On GNU, NetBSD and FreeBSD the following works:

    $ echo xy >f
    $ grep 'xy\?' f; echo $?
    xy
    0

The same goes for "\+". The "?" and "+" syntax is not in the BRE
syntax, just in ERE, but on some implementations it can be invoked by
prefixing the meta-operator with "\", but not on OpenBSD:

Yup, thanks for testing, spotting and fixing.  I do recall finding
one of these during my review during recent couple of cycles, but
apparently eyeballing will not always catch everything X-<.