compose-char is buggy on Windows

[Peter De Wachter]

The compose-char function seems to have problems on Windows. For
example, if you try the following:

  (compose-region 1 5 (decode-char 'ucs #x221E))

Emacs should display the first few characters of the buffer as an
infinity symbol (Unicode #x221E). Instead, it produces some garbled
character. On GNU/Linux (both console and GTK interface), this works.

This happens for most but not all characters: if I try this trick with
a latin-1 character, it works right. For fancy Unicode symbols, it
never seems to work. This doesn't seem to depend on the font
used. 

In GNU Emacs 22.1.1 (i386-mingw-nt5.1.2600)
 of 2007-06-02 on RELEASE
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (3.4) --cflags -Ic:/gnuwin32/include'

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: NLB
  locale-coding-system: cp1252
  default-enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  encoded-kbd-mode: t
  tooltip-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  auto-compression-mode: t
  line-number-mode: t

Recent input:
M-x r e p o r t SPC e m SPC b SPC <return>

Recent messages:
("C:\\Documents and Settings\\Peter\\Bureaublad\\emacs-22.1\\bin\\emacs.exe")
Loading encoded-kb...done
For information about the GNU Project and its goals, type C-h C-p. [2 times]
Loading emacsbug...
Loading regexp-opt...done
Loading emacsbug...done