Add :coding support to open-network-stream and open-gnutls-stream

* doc/lispref/processes.texi (Network): Describe :coding keyword support.

* doc/misc/emacs-gnutls.texi (Help For Developers): Describe :coding
keyword support.

* etc/NEWS: Announce change to open-network-stream and
open-gnutls-stream.

* lisp/net/gnutls.el (open-gnutls-stream): Add support for :coding, pass it
down to open-network-stream.

* lisp/net/network-stream.el (open-network-stream)
(network-stream-open-plain, network-stream-open-starttls): Add
support for :coding, pass it down to make-network-process.
(network-stream-open-shell): Add support-for :coding, use
set-process-coding-system to set it after process creation.

2 files changed, 7 insertions, 1 deletions

diff --git a/doc/lispref/processes.texi b/doc/lispref/processes.texi
index 14cd079c563..735e9fd7db4 100644
--- a/doc/lispref/processes.texi
+++ b/doc/lispref/processes.texi
@@ -2463,6 +2463,12 @@ that are mainly relevant to encrypted connections:
 @item :nowait @var{boolean}
 If non-@code{nil}, try to make an asynchronous connection.
 
+@item :coding @var{coding}
+Use this to set the coding systems used by the network process, in
+preference to binding @code{coding-system-for-read} or
+@code{coding-system-for-write}.  @xref{Network Processes} for
+details.
+
 @item :type @var{type}
 The type of connection.  Options are:
 
diff --git a/doc/misc/emacs-gnutls.texi b/doc/misc/emacs-gnutls.texi
index 555a4b1b56e..c3e69178fca 100644
--- a/doc/misc/emacs-gnutls.texi
+++ b/doc/misc/emacs-gnutls.texi
@@ -190,7 +190,7 @@ the connection process.
 
 The optional @var{parameters} argument is a list of keywords and
 values.  The only keywords which currently have any effect are
-@code{:client-certificate} and @code{:nowait}.
+@code{:client-certificate}, @code{:nowait}, and @code{:coding}.
 
 Passing @w{@code{:client certificate t}} triggers looking up of client
 certificates matching @var{host} and @var{service} using the