Re: RFA: always default to using the libiberty regex

[Mark Kettenis <m dot kettenis at osp dot nl>]

Sorry for my late reply, but I was on vacation last week.

First, Martin's patch isn't right as is; it should at least update the
string that documents --without-included-regex.  If we apply it, I'd
also like to see a comment somewhere, presumably in configure.in, that
says that we used to default to --without-included-regex on systems
with version 2 of the GNU C library, but don't do that anymore since
there are systems out there that have a badly performing GNU regex in
libc.

Anyway, the history about GDB prefering the installed regex is a bit
blurred.  We used to prefer the regex in libc on Linux systems.  We
discussed turning it off one time, but I remember serious opposition
against it, so we left it on.  However, apparently somewhere along the
line the configuration stuff got broken, and we silently moved to
always using the bundled regex.  I recently fixed the configuration
problem, such that we started using the regex in libc again on Linux
systems.

If it is easy to detect a broken regex implementation, we should add
configury stuff to do so, otherwise we should just yank it as Martin's
patch does.

Mark