bug#6886: 24.0.50; emacs --unibyte doesn't work

[Kenichi Handa]

When I run Emacs as this:

% emacs --unibyte

Emacs doesn't start, but this error message is shown:
emacs: Attempt to set a constant symbol: enable-multibyte-characters

Emacs 23 doesn't has this problem.

---
Kenichi Handa
handa@m17n.org

In GNU Emacs 24.0.50.35 (i686-pc-linux-gnu, GTK+ Version 2.20.1)
 of 2010-08-18 on etlken
Windowing system distributor `The X.Org Foundation', version 11.0.10706000
configured using `configure  '--enable-asserts' 'CFLAGS=-g''

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: ja_JP.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  display-time-mode: t
  tooltip-mode: t
  mouse-wheel-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

Recent input:
<help-echo> M-x r e p o r t <tab> <tab> e - <backspace> 
<backspace> <backspace> <tab> <return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
/usr/local/share/emacs/site-lisp/lookup-utils hides 
/usr/local/share/emacs/site-lisp/lookup/lookup-utils
/usr/local/share/emacs/site-lisp/lookup-vars hides 
/usr/local/share/emacs/site-lisp/lookup/lookup-vars
/usr/local/share/emacs/site-lisp/ndkks hides 
/usr/local/share/emacs/site-lisp/lookup/ndkks
/usr/local/share/emacs/site-lisp/stem-english hides 
/usr/local/share/emacs/site-lisp/lookup/stem-english
/usr/local/share/emacs/site-lisp/sdicf hides 
/usr/local/share/emacs/site-lisp/lookup/sdicf
/usr/local/share/emacs/site-lisp/ndict hides 
/usr/local/share/emacs/site-lisp/lookup/ndict
/usr/local/share/emacs/site-lisp/lookup-content hides 
/usr/local/share/emacs/site-lisp/lookup/lookup-content
/usr/local/share/emacs/site-lisp/lookup hides 
/usr/local/share/emacs/site-lisp/lookup/lookup
/usr/local/share/emacs/site-lisp/ndspell hides 
/usr/local/share/emacs/site-lisp/lookup/ndspell
/usr/local/share/emacs/site-lisp/ndeb hides 
/usr/local/share/emacs/site-lisp/lookup/ndeb
/usr/local/share/emacs/site-lisp/lookup-types hides 
/usr/local/share/emacs/site-lisp/lookup/lookup-types
/usr/local/share/emacs/site-lisp/ndsrd hides 
/usr/local/share/emacs/site-lisp/lookup/ndsrd
/usr/local/share/emacs/site-lisp/ndcookie hides 
/usr/local/share/emacs/site-lisp/lookup/ndcookie
/usr/local/share/emacs/site-lisp/lookup-select hides 
/usr/local/share/emacs/site-lisp/lookup/lookup-select
/usr/local/share/emacs/site-lisp/ndic hides 
/usr/local/share/emacs/site-lisp/lookup/ndic
/usr/local/share/emacs/site-lisp/ndtp hides 
/usr/local/share/emacs/site-lisp/lookup/ndtp
/usr/local/share/emacs/site-lisp/egg/leim-list hides 
/usr/local/work/emacs/work/leim/leim-list
/usr/local/share/emacs/site-lisp/rmail-mime/mime/pgg-parse hides 
/usr/local/work/emacs/work/lisp/pgg-parse
/usr/local/share/emacs/site-lisp/rmail-mime/mail/sha1 hides 
/usr/local/work/emacs/work/lisp/sha1
/usr/local/share/emacs/site-lisp/rmail-mime/mime/pgg-gpg hides 
/usr/local/work/emacs/work/lisp/pgg-gpg
/usr/local/share/emacs/site-lisp/rmail-mime/mail/hex-util hides 
/usr/local/work/emacs/work/lisp/hex-util
/usr/local/share/emacs/site-lisp/rmail-mime/mime/pgg hides 
/usr/local/work/emacs/work/lisp/pgg
/usr/local/share/emacs/site-lisp/rmail-mime/mime/pgg-pgp hides 
/usr/local/work/emacs/work/lisp/pgg-pgp
/usr/local/share/emacs/site-lisp/rmail-mime/mime/pgg-def hides 
/usr/local/work/emacs/work/lisp/pgg-def
/usr/local/share/emacs/site-lisp/rmail-mime/mime/pgg-pgp5 hides 
/usr/local/work/emacs/work/lisp/pgg-pgp5
/usr/local/share/emacs/site-lisp/rmail-mime/mail/hmac-def hides 
/usr/local/work/emacs/work/lisp/net/hmac-def
/usr/local/share/emacs/site-lisp/rmail-mime/mail/hmac-md5 hides 
/usr/local/work/emacs/work/lisp/net/hmac-md5
/usr/local/share/emacs/site-lisp/rmail-mime/mail/sasl-digest hides 
/usr/local/work/emacs/work/lisp/net/sasl-digest
/usr/local/share/emacs/site-lisp/rmail-mime/mail/sasl-cram hides 
/usr/local/work/emacs/work/lisp/net/sasl-cram
/usr/local/share/emacs/site-lisp/rmail-mime/mail/sasl hides 
/usr/local/work/emacs/work/lisp/net/sasl
/usr/local/share/emacs/site-lisp/rmail-mime/mail/smtpmail hides 
/usr/local/work/emacs/work/lisp/mail/smtpmail
/usr/local/share/emacs/site-lisp/rmail-mime/mail/feedmail hides 
/usr/local/work/emacs/work/lisp/mail/feedmail
/usr/local/share/emacs/site-lisp/egg/its/thai hides 
/usr/local/work/emacs/work/lisp/language/thai
/usr/local/share/emacs/site-lisp/egg/its/greek hides 
/usr/local/work/emacs/work/lisp/language/greek
/usr/local/share/emacs/site-lisp/rmail-mime/mime/smime hides 
/usr/local/work/emacs/work/lisp/gnus/smime
/usr/local/work/emacs/work/lisp/language/thai-word hides ~/emacslisp/thai-word
/usr/local/work/emacs/work/lisp/textmodes/tex-mode hides ~/emacslisp/tex-mode
/usr/local/work/emacs/work/lisp/textmodes/table hides ~/emacslisp/table
/usr/local/work/emacs/work/lisp/emacs-lisp/syntax hides ~/emacslisp/syntax
/usr/local/work/emacs/work/lisp/progmodes/prolog hides ~/emacslisp/prolog

Features:
(shadow sort gnus-util mail-extr message rfc822 mml easymenu
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader emacsbug package time
sendmail regexp-opt rmail-sa rmailsum rmail mail-utils
rfc2047 rfc2045 ietf-drums mm-util mail-prsvr japan-util
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 system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty
emacs)