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

[Michal Privoznik]

On 01/15/2018 12:30 PM, Andrea Bolognani wrote:
> On Mon, 2018-01-15 at 10:26 +0100, Andrea Bolognani wrote:
>> macOS has brew, though. I've kicked off a Travis build with this
>> commit[1] included, let's see whether configure picks up readline
>> installed from brew instead of the obsolete one available in the
>> base system.
> 
> Nope, it still picks up the one shipped with the OS :/
> 
>> If it does, then we can omit your patch and... Document the version
>> requirement somehow? If we used pkg-config to detect readline
>> availability, that would be easy. Alas, readline only introduced
>> pkg-config support relatively recently, so we can't do that.
> 
> 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;

I just found out that this will not work - even though there is
readline.pc.in in the readline repo, they are lacking rule to install
the .pc file. So nobody ships that. For instance, on my rawhide box:

[root at fedora ~]# rpm -q readline
readline-7.0-5.fc26.x86_64
[root at fedora ~]# rpm -ql readline | grep \.pc
[root at fedora ~]#

> 
>   * 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 should have commented earlier too - what good it is to switch to
pkg-config if we're keeping the old way of detecting the library (with
this patch included) anyway?

Therefore I think we should merge this patch and switch to pkg-config
later (when distros have it).

Michal