Greek end sigmas cannot be up/down cased

[Frederik Fouvry]

Symptoms:

In Greek, downcase-word() and upcase-word() do not work correctly for
the end sigma.

$ emacs -q --no-site-file
M-x set-language-environment RET greek RET
C-\
s a w ;; (This reads in Greek as "sas")
C-a
M-u
;; only the first two characters are converted, the last one is not.
;; It should be the same as the first: a capital sigma

RET
S A W ;; (the same as above but in upper case; S A S gives the same
      ;; result - that is OK)
C-a
M-l
;; the three characters are converted, but to the equivalent of s a s
;; not to s a w.


In GNU Emacs 21.3.50.19 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2004-11-25 on cc.at.coli.uni-sb.de
Distributor `The XFree86 Project, Inc', version 11.0.40201000
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: POSIX
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: address@hidden
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_GB
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t

Major mode: LaTeX

Minor modes in effect:
  reftex-mode: t
  auto-image-file-mode: t
  desktop-save-mode: t
  global-auto-revert-mode: t
  iswitchb-mode: t
  which-function-mode: t
  show-paren-mode: t
  recentf-mode: t
  display-time-mode: t
  auto-insert-mode: t
  auto-compression-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t
  abbrev-mode: t

Recent input:
<mouse-2> <down-mouse-1> <mouse-1> C-e SPC x ) ) C-a 
<right> <right> <right> <right> <right> <right> <right> 
<right> <right> <down-mouse-1> <mouse-1> C-k C-a <right> 
<right> <right> <right> <right> <right> <right> <right> 
<right> <right> <backspace> C-e ( ) SPC i n c o r e 
e c <backspace> <backspace> r <backspace> e <backspace> 
<backspace> r e c t SPC i n SPC G r e e k <escape> 
<backspace> <escape> <backspace> f o r SPC G r e e 
k C-c C-f C-b f o u v r y C-c C-c x x n <return> <help-echo> 
<help-echo> <help-echo> <help-echo> <menu-bar> <help-menu> 
<report-emacs-bug>

Recent messages:
(Next local Ispell command will use british dictionary)
Starting new Ispell process...
Spell checking region using british dictionary...
Exited spell-checking
Spell checking region using british dictionary...
Exited spell-checking
Sign message ? (y or n) 
Unfrobbing selective-display...
Sending...done
Loading emacsbug...done