* lisp/net/gnutls.el (gnutls-negotiate): Use CL-style keyword arguments
instead of positional arguments. Allow :keylist and :crlfiles
arguments.
(open-gnutls-stream): Call it.
* lisp/net/network-stream.el (network-stream-open-starttls): Adjust to
call `gnutls-negotiate' with :process and :hostname arguments.
* configure.in: Set up GnuTLS.
* lisp/net/gnutls.el: GnuTLS glue code to set up a connection.
* src/Makefile.in (LIBGNUTLS_LIBS, LIBGNUTLS_CFLAGS, ALL_CFLAGS)
(obj, LIBES): Set up GnuTLS support.
* src/config.in: Set up GnuTLS support.
* src/emacs.c: Set up GnuTLS support and call syms_of_gnutls.
* src/gnutls.c: The source code for GnuTLS support in Emacs.
* src/gnutls.h: The GnuTLS glue for Emacs, macros and enums.
* src/process.c (make_process, Fstart_process)
(read_process_output, send_process): Set up GnuTLS support for
process input/output file descriptors.
* src/process.h: Set up GnuTLS support.