bug#21839: 25.0.50; can't use newlines in defaults in cl functions

[Paul M. Rodriguez]

Defining a function using the `cl' package with an optional argument
whose default contains a newline causes an error with the message
"Unrecognized usage format".

Example:


(require 'cl-lib)
(cl-defun example (&optional (separator "\n"))
 ())
;; Unrecognized usage format


The problem appears to be due to a change to `help-add-fundoc-usage'
introduced in this commit:

https://lists.gnu.org/archive/html/emacs-diffs/2015-10/msg00365.html

Paul Rodriguez.


In GNU Emacs 25.0.50.2 (x86_64-pc-linux-gnu, GTK+ Version 3.10.8)
of 2015-11-03
Windowing system distributor 'The X.Org Foundation', version 
11.0.11600000
System Description:     Ubuntu 14.04.3 LTS

Configured using:
'configure --build=x86_64-linux-gnu --prefix=/usr
'--includedir=${prefix}/include' '--mandir=${prefix}/share/man'
'--infodir=${prefix}/share/info' --sysconfdir=/etc --localstatedir=/var
'--libdir=${prefix}/lib/x86_64-linux-gnu'
'--libexecdir=${prefix}/lib/x86_64-linux-gnu' --disable-maintainer-mode
--disable-dependency-tracking --prefix=/usr --sharedstatedir=/var/lib
--program-suffix=-snapshot --with-x=yes --with-x-toolkit=gtk3
'CFLAGS=-g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat
-Werror=format-security' CPPFLAGS=-D_FORTIFY_SOURCE=2
'LDFLAGS=-Wl,-Bsymbolic-functions -Wl,-z,relro''

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS
NOTIFY LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
 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

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Type C-x 1 to delete the help window.
Scanning for dabbrevs...done
user-error: No dynamic expansion for ‘user-mail-add’ found

"pmr@ruricolist.com"
Quit [4 times]

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message dired format-spec
rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util mail-prsvr mail-utils cl-extra dabbrev help-fns help-mode
easymenu cl-loaddefs pcase cl-lib time-date mule-util tooltip eldoc
electric uniquify ediff-hook vc-hooks lisp-float-type mwheel x-win
term/common-win x-dnd 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 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 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
dbusbind inotify dynamic-setting system-font-setting font-render-setting
move-toolbar gtk x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 81136 4848)
(symbols 48 19075 0)
(miscs 40 48 85)
(strings 32 12781 5416)
(string-bytes 1 371247)
(vectors 16 10746)
(vector-slots 8 412657 7275)
(floats 8 136 182)
(intervals 56 257 16)
(buffers 976 12)
(heap 1024 32881 1060))