Rework the mechanisms for async GnuTLS connections

* lisp/net/gnutls.el (open-gnutls-stream): Compute the
gnutls-boot parameters and pass them to the process object.
(gnutls-negotiate): New parameter :return-keywords that won't
connect to anything, just compute the keywords.

* lisp/url/url-http.el (url-http): Revert async TLS sentinel
hack, which is no longer necessary.

* src/gnutls.c (Fgnutls_asynchronous_parameters): Rename from
gnutls-mark-process.

* src/process.c (connect_network_socket): If we're connecting to
an asynchronous TLS socket, complete the GnuTLS boot sequence here.

* src/process.h: New parameter gnutls_async_parameters.

1 files changed, 6 insertions, 3 deletions

diff --git a/doc/misc/emacs-gnutls.texi b/doc/misc/emacs-gnutls.texi
index 1db6c517de8..75fd97c7c74 100644
--- a/doc/misc/emacs-gnutls.texi
+++ b/doc/misc/emacs-gnutls.texi
@@ -181,9 +181,6 @@ syntax are the same as those given to @code{open-network-stream}
 Manual}).  The connection process is called @var{name} (made unique if
 necessary).  This function returns the connection process.
 
-If called with @var{nowait}, the process is returned immediately
-(before connecting to the server).
-
 @lisp
 ;; open a HTTPS connection
 (open-gnutls-stream "tls" "tls-buffer" "yourserver.com" "https")
@@ -194,6 +191,12 @@ If called with @var{nowait}, the process is returned immediately
 
 @end defun
 
+@findex gnutls-asynchronous-parameters
+If called with @var{nowait}, the process is returned immediately
+(before connecting to the server).  In that case, the process object
+is told what parameters to use when negotiating the connection
+by using the @code{gnutls-asynchronous-parameters} function.
+
 The function @code{gnutls-negotiate} is not generally useful and it
 may change as needed, so please see @file{gnutls.el} for the details.