The window-width function does not take text scale adjustments
into account.  This breaks code such as
http://www.emacswiki.org/emacs/ErcFilling#toc2 which is meant to
insert timestamps aligned to the right edge of the window.

To reproduce starting from emacs -Q,
1) M-: (window-width) RET  ; returns 80 here
2) C-x C-=                 ; window is now 70 characters wide
3) M-: (window-width) RET  ; still returns 80



In GNU Emacs 24.0.91.1 (x86_64-apple-darwin, NS apple-appkit-1038.35)
 of 2011-10-30 on virtualmac.porkrind.org
Windowing system distributor `Apple', version 10.3.1038
configured using `configure  '--host=x86_64-apple-darwin'
'--build=i686-apple-darwin' '--with-ns' 'build_alias=i686-apple-darwin'
'host_alias=x86_64-apple-darwin' 'CC=gcc -mmacosx-version-min=10.5''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.US-ASCII
  value of $XMODIFIERS: nil
  locale-coding-system: us-ascii-unix
  default enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  text-scale-mode: t
  tooltip-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 input:
M-x e m a c s - v e r <tab> <return> C-x 3 M-: ( w
i n d o w - w i d t h ) <return> C-x C-= C-x C-= M-:
<up> <return> C-x 1 M-x r e p o r t - e m <tab> <r
eturn>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
GNU Emacs 24.0.91.1 (x86_64-apple-darwin, NS apple-appkit-1038.35) of
2011-10-30 on virtualmac.porkrind.org
37 (#o45, #x25)
37 (#o45, #x25)

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr message format-spec rfc822 mml easymenu
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mailabbrev mail-utils gmm-utils mailheader
emacsbug face-remap time-date tooltip ediff-hook vc-hooks
lisp-float-type mwheel ns-win tool-bar dnd fontset image fringe
lisp-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 loaddefs button faces cus-face files text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process ns multi-tty
emacs)