bug#6856: 24.0.50; fill-paragraph always marks buffer as modified

[Jose Antonio Ortega Ruiz]

1. emacs -Q
2. Open any file, go to a filled paragraph spawning more than 1 line
3. M-q. If the paragraph was already filled, no modification of the
   buffer occurs, but the buffer is marked as modified nonetheless.
3'. If the first M-q actually modified the text, save the buffer and go
    to 3: a second M-q does not change the text but marks the buffer as
    modified.


In GNU Emacs 24.0.50.1 (i486-pc-linux-gnu, GTK+ Version 2.20.1)
 of 2010-08-08 on elegiac, modified by Debian
 (emacs-snapshot package, version 1:20100808-1)
configured using `configure  '--build' 'i486-linux-gnu' '--host' 
'i486-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib' 
'--libexecdir=/usr/lib' '--localstatedir=/var' '--infodir=/usr/share/info' 
'--mandir=/usr/share/man' '--with-pop=yes' 
'--enable-locallisppath=/etc/emacs-snapshot:/etc/emacs:/usr/local/share/emacs/24.0.50/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.0.50/site-lisp:/usr/share/emacs/site-lisp'
 '--without-compress-info' '--with-x=yes' '--with-x-toolkit=gtk' 
'build_alias=i486-linux-gnu' 'host_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN 
-DSITELOAD_PURESIZE_EXTRA=5000 -g -O2' 'LDFLAGS=-g -Wl,--as-needed' 'CPPFLAGS=''

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.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Text

Minor modes in effect:
  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
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
C-x C-f / t m p / f o o . t x t RET a SPC b SPC c SPC 
d e C-x C-s ESC q C-a ESC q C-o C-x C-s a SPC d k f 
j l a SPC d k j f ESC q C-x C-s ESC q C-e RET a l d 
k f j SPC l s k d f j SPC a l k d j f RET l a k s d 
f j C-x C-s ESC q C-x C-s ESC q SPC s k d f j SPC a 
l s k j f SPC a l s k f j ESC q SPC a s l k ESC q C-x 
C-s ESC q C-x C-s ESC q C-x C-s C-h k ESC q ESC x r 
e p o r t - b u TAB RET

Recent messages:
Wrote /tmp/foo.txt
Saving file /tmp/foo.txt...
Wrote /tmp/foo.txt
Saving file /tmp/foo.txt...
Wrote /tmp/foo.txt
Saving file /tmp/foo.txt...
Wrote /tmp/foo.txt
Saving file /tmp/foo.txt...
Wrote /tmp/foo.txt
Type C-x 1 to delete the help window.

Load-path shadows:
/etc/emacs/site-start hides /usr/local/share/emacs/site-lisp/site-start
/usr/share/emacs/24.0.50/site-lisp/debian-startup hides 
/usr/share/emacs/site-lisp/debian-startup
/usr/local/share/emacs/site-lisp/cedet/speedbar/sb-image hides 
/usr/share/emacs/24.0.50/lisp/sb-image
/usr/local/share/emacs/site-lisp/cedet/speedbar/dframe hides 
/usr/share/emacs/24.0.50/lisp/dframe
/usr/local/share/emacs/site-lisp/cedet/speedbar/speedbar hides 
/usr/share/emacs/24.0.50/lisp/speedbar
/usr/local/share/emacs/site-lisp/cedet/common/ezimage hides 
/usr/share/emacs/24.0.50/lisp/ezimage
/usr/local/share/emacs/site-lisp/cedet/eieio/eieio hides 
/usr/share/emacs/24.0.50/lisp/emacs-lisp/eieio
/usr/local/share/emacs/site-lisp/cedet/eieio/eieio-base hides 
/usr/share/emacs/24.0.50/lisp/emacs-lisp/eieio-base
/usr/local/share/emacs/site-lisp/cedet/eieio/eieio-opt hides 
/usr/share/emacs/24.0.50/lisp/emacs-lisp/eieio-opt
/usr/local/share/emacs/site-lisp/cedet/eieio/eieio-datadebug hides 
/usr/share/emacs/24.0.50/lisp/emacs-lisp/eieio-datadebug
/usr/local/share/emacs/site-lisp/cedet/eieio/eieio-custom hides 
/usr/share/emacs/24.0.50/lisp/emacs-lisp/eieio-custom
/usr/local/share/emacs/site-lisp/cedet/eieio/eieio-comp hides 
/usr/share/emacs/24.0.50/lisp/emacs-lisp/eieio-comp
/usr/local/share/emacs/site-lisp/cedet/eieio/chart hides 
/usr/share/emacs/24.0.50/lisp/emacs-lisp/chart
/usr/local/share/emacs/site-lisp/cedet/eieio/eieio-speedbar hides 
/usr/share/emacs/24.0.50/lisp/emacs-lisp/eieio-speedbar
/usr/local/share/emacs/site-lisp/cedet/common/mode-local hides 
/usr/share/emacs/24.0.50/lisp/cedet/mode-local
/usr/local/share/emacs/site-lisp/cedet/common/inversion hides 
/usr/share/emacs/24.0.50/lisp/cedet/inversion
/usr/local/share/emacs/site-lisp/cedet/semantic/semantic hides 
/usr/share/emacs/24.0.50/lisp/cedet/semantic
/usr/local/share/emacs/site-lisp/cedet/common/cedet-global hides 
/usr/share/emacs/24.0.50/lisp/cedet/cedet-global
/usr/local/share/emacs/site-lisp/cedet/common/cedet-files hides 
/usr/share/emacs/24.0.50/lisp/cedet/cedet-files
/usr/local/share/emacs/site-lisp/cedet/srecode/srecode hides 
/usr/share/emacs/24.0.50/lisp/cedet/srecode
/usr/local/share/emacs/site-lisp/cedet/common/cedet hides 
/usr/share/emacs/24.0.50/lisp/cedet/cedet
/usr/local/share/emacs/site-lisp/cedet/common/cedet-idutils hides 
/usr/share/emacs/24.0.50/lisp/cedet/cedet-idutils
/usr/local/share/emacs/site-lisp/cedet/common/pulse hides 
/usr/share/emacs/24.0.50/lisp/cedet/pulse
/usr/local/share/emacs/site-lisp/cedet/ede/ede hides 
/usr/share/emacs/24.0.50/lisp/cedet/ede
/usr/local/share/emacs/site-lisp/cedet/common/cedet-cscope hides 
/usr/share/emacs/24.0.50/lisp/cedet/cedet-cscope
/usr/local/share/emacs/site-lisp/cedet/common/data-debug hides 
/usr/share/emacs/24.0.50/lisp/cedet/data-debug

Features:
(shadow sort gnus-util mail-extr message sendmail regexp-opt rfc822 mml
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 help-fns help-mode easymenu view tooltip ediff-hook vc-hooks
lisp-float-type mwheel x-win x-dnd tool-bar dnd fontset image fringe
lisp-mode register page menu-bar rfn-eshadow timer select scroll-bar
mldrag 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 loaddefs button minibuffer faces cus-face files text-properties
overlay md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process dbusbind
dynamic-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty emacs)