bug#19395: 25.0.50; Setting left fringe to 0 messes up window-width

[Titus von der Malsburg]

- emacs -Q
- (set-fringe-mode '(0 . 2))
  The left fringe has to be zero, the right fringe doesn't seem to matter.
- Fill a line completely with n characters such that it doesn't break.
- (window-width) reports n+1 characters instead of n.

This bug is potentially related to this one: 
https://lists.gnu.org/archive/html/bug-gnu-emacs/2014-10/msg00061.html



In GNU Emacs 25.0.50.2 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8)
 of 2014-12-13 on montana
Repository revision: 49daed60510a073062b41fa39fd7c010cb0a315e
Windowing system distributor `The X.Org Foundation', version 11.0.11501000
System Description:     Ubuntu 14.04.1 LTS

Configured using:
 `configure --prefix=/home/malsburg/usr/
 PKG_CONFIG_PATH=/usr/local/X11R6.8/lib/pkgconfig'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND DBUS GSETTINGS NOTIFY
GNUTLS LIBXML2 FREETYPE XFT ZLIB

Important settings:
  value of $LC_MONETARY: en_GB.UTF-8
  value of $LC_NUMERIC: en_GB.UTF-8
  value of $LC_TIME: en_GB.UTF-8
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  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

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
scroll-up-command: End of buffer
ESC <mouse-1> is undefined
Mark set [7 times]
((left-fringe . 0) (right-fringe . 2))
50 (#o62, #x32, ?2)

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message dired format-spec
rfc822 mml easymenu mml-sec mm-decode mm-bodies mm-encode mail-parse
rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045
ietf-drums mm-util help-fns mail-prsvr mail-utils mule-util time-date
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel x-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 cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese hebrew greek
romanian slovak czech european ethiopic indian cyrillic chinese
case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer 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 make-network-process dbusbind
gfilenotify dynamic-setting system-font-setting font-render-setting
move-toolbar gtk x-toolkit x multi-tty emacs)

Memory information:
((conses 16 77284 9243)
 (symbols 48 18162 1)
 (miscs 40 53 174)
 (strings 32 11417 4672)
 (string-bytes 1 307454)
 (vectors 16 10084)
 (vector-slots 8 394429 11468)
 (floats 8 73 226)
 (intervals 56 215 0)
 (buffers 976 11)
 (heap 1024 31835 1054))