bug#23503: 25.1.50; url-retrieve-synchronously doesn't work for https anymore ?

[Chunyang Xu]

The following always display a empty buffer

(display-buffer
 (url-retrieve-synchronously "https://gnu.org/software/emacs/";))

Emacs is started with 'open -a Emacs --args -Q' on Mac OS X. gnutls
(3.4.11) is installed via homebrew. 'M-! gnutls-cli --version' displays
the gnutls version correctly.

In GNU Emacs 25.1.50.7 (x86_64-apple-darwin15.4.0, NS appkit-1404.46
Version 10.11.4 (Build 15E65))
 of 2016-05-10 built on MBA.local
Repository revision: c20cc0986cdade6577d6ce169330db19e2169794
Windowing system distributor 'Apple', version 10.3.1404
Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Mark set
Contacting host: gnu.org:443
Scanning for dabbrevs...done

Configured using:
 'configure --with-modules'

Configured features:
JPEG RSVG IMAGEMAGICK NOTIFY ACL GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS
NS MODULES

Important settings:
  value of $LC_ALL: en_US.UTF-8
  value of $LC_CTYPE: UTF-8
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr dabbrev emacsbug message dired dired-loaddefs
format-spec rfc822 mml mml-sec epa derived epg epg-config gnus-util
rmail rmail-loaddefs mm-decode mm-bodies mm-encode mailabbrev gmm-utils
mailheader sendmail mail-utils network-stream starttls url-http tls
gnutls mail-parse rfc2231 rfc2047 rfc2045 mm-util ietf-drums mail-prsvr
url-gw nsm puny seq url-cache url-auth url url-proxy url-privacy
url-expand url-methods url-history url-cookie url-domsuf url-util
url-parse auth-source cl-seq eieio byte-opt bytecomp byte-compile
cl-extra help-mode easymenu cconv eieio-core cl-macs gv eieio-loaddefs
cl-loaddefs pcase cl-lib password-cache url-vars mailcap time-date
mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel term/ns-win ns-win ucs-normalize term/common-win
tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment
elisp-mode lisp-mode prog-mode register page menu-bar rfn-eshadow timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese charscript case-table epa-hook jka-cmpr-hook help simple abbrev
obarray minibuffer cl-preloaded nadvice loaddefs button faces cus-face
macroexp files text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget hashtable-print-readable backquote kqueue
cocoa ns multi-tty make-network-process emacs)

Memory information:
((conses 16 215850 8508)
 (symbols 48 21946 0)
 (miscs 40 47 206)
 (strings 32 22454 6562)
 (string-bytes 1 679049)
 (vectors 16 36037)
 (vector-slots 8 677603 6591)
 (floats 8 217 28)
 (intervals 56 222 0)
 (buffers 976 12))