[libvirt] [PATCH 3/3] m4: Check for rl_completion_quote_character

[Andrea Bolognani]

On Mon, 2018-01-15 at 13:31 +0100, Michal Privoznik wrote:
> > So, one way to solve this once and for all would be to:
> > 
> >   * try looking up readline through pkg-config. If that works,
> >     then we already know we're compiling against a recent
> >     readline version and everything will work;
> > 
> >   * if readline's pkg-config file is not available, try linking
> >     against it the old way. This will succeed on oldish versions
> >     like the one shipped with CentOS but fail because of missing
> >     functions on macOS.
> > 
> > I could try cooking up something like the above, but I can never
> > seem to get it right the first couple of times when m4 is involved,
> > so in the interest of time - and not having to merge this patch you
> > hate ;) - would you mind looking into it yourself instead?
> 
> The reason I hate this patch is not because the patch itself looks ugly.
> It's because we have to deal with the situation in the first place and
> invest our time in resolving it. And what you're suggesting might sound
> right but we'll end up with the same situation after all.

I don't think that's the case. Right now we have to work around
issues in macOS all the time because we're linking against the
obsolete readline version included in the base system; if we
implemented what I propose above, then we could just mandate that
readline 6.0 or newer is required. macOS builds would then fail
unless you install a recent readline using brew, but that's
entirely acceptable, and we would have obtained a reasonable
baseline to work against going forward. Plus it would allow us to
get rid of some nasty hacks[1] on our CI as well :)


[1] https://github.com/libvirt/libvirt-jenkins-ci/blob/635a1e22806c525a11d80fc32cc664bb672f65fa/guests/tasks/compat.yml#L18-L31
-- 
Andrea Bolognani / Red Hat / Virtualization