gnutls infloop possibly fixed

[Lars Ingebrigtsen <larsi@gnus.org>]

I finally took a hard look at the GnuTLS-related Emacs hangs.  It turned
out to be pretty easy to reproduce for me.  If I switch off the wifi on
this laptop and then presses `g' in Gnus, Emacs would reliably use 100%
CPU, and `C-g' or anything wouldn't work.  So a totally dead Emacs.

I chased this down to emacs_gnutls_write, which would just, well,
infloop if libgnutls returned EAGAIN.  I've now removed that, and just
leaves the normal Emacs process loop to retry if we get an EAGAIN.

This seems to work for me -- `C-g' reliably works for me if I drop the
network, or I get a new IP address.

There may be other side-effects, though.  Slower throughput?  I don't
know.  Please give it a whirl and report back whether things stop
working or not.

-- 
(domestic pets only, the antidote for overdose, milk.)
  http://lars.ingebrigtsen.no  *  Sent from my Rome