[libvirt] gnulib compiler warning detection broken on RHEL5 autoconf

[Eric Blake]

On 07/26/2011 04:45 AM, Daniel P. Berrange wrote:
> I was wondering why I didn't see any compile warnings from the broken
> gnutls code on RHEL5 when I noticed that we were building without any
> compiler warning flags at all.
>
> It seems configure fails on RHEL5 vintage autoconf
>
>    checking whether compiler handles -Wall... ./configure: line 75468: ${$as_gl_Warn+set}: bad substitution

Yuck.  I'll take a look (it may be that older autoconf has a bug, and I 
merely need to backport a workaround for that bug fix).

> I'm guessing it is the gl_WARN_ADD() macro that is at fault somehow.

Very possible, in fact, it may be a case of gl_WARN_ADD using an 
autoconf macro and assuming newer semantics, where a bit more work is 
needed to guarantee support with autoconf 2.59.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org