bug#32446: Configure-time requirement for gnutls is too old

[Eli Zaretskii]

> From: Gavin Smith <gavinsmith0123@gmail.com>
> Date: Sat, 15 Sep 2018 16:55:09 +0100
> Cc: Noam Postavsky <npostavs@gmail.com>, tzz@lifelogs.com,
>         32446@debbugs.gnu.org
> 
> On Sat, Sep 15, 2018 at 06:26:51PM +0300, Eli Zaretskii wrote:
> > Gavin, can you test this with your version of GnuTLS?
> 
> I applied Noam's patch, reconfigured to enable GnuTLS, and ran "make", 
> and the build completed successfully.

Thanks.

The patch LGTM as well, so, Noam, please push eto emacs-26, and
thanks.