cwarn/font-lock problem under HP-UX 10.20

[Klaus Zeitler]

This bug report will be sent to the Free Software Foundation,
not to your local site managers!
Please write in English, because the Emacs maintainers do not have
translators to read other languages for them.

Your bug report will be posted to the bug-gnu-emacs@gnu.org mailing list,
and to the gnu.emacs.bug news group.

In GNU Emacs 21.1.2 (hppa2.0-hp-hpux10.20, OSF/Motif Version 1.2.6)
 of 2001-11-29 on nbghs10
configured using `configure  --with-gcc 
--prefix=/vol/freeware/HP-UX-B.10.20/emacs/21.1 
--sharedstatedir=/vol/freeware/HP-UX-B.10.20/emacs/21.1/share 
--with-x-toolkit=motif --x-includes=/usr/include/X11R6:/usr/local/gnu/include 
--x-libraries=/usr/lib/X11R6:/usr/local/gnu/lib --with-pop'
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: C.iso88591
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

1. start emacs with -q
2. M-x: global-font-lock-mode
3. in scratch buffer execute (add-hook 'c-mode-hook 'turn-on-cwarn-mode)
4. load e.g. the following buggy C file:

1  main ()
2  {
3    int x=5;
4    if (x=1);
5    {
6    }
7  }

5. in line 4 the "=" and the ";" should be highlighted with
   font-lock-warning face, but they aren't

6. turn off cwarn-mode and turn it on again with twice
   M-x cwarn-mode
   now line 4 is correctly highlighted


When I execute the first 4 steps on my GNU/Linux PC line 4 is
correctly highlighted, but not under HP-UX. I'm puzzled, this
is the first time that syntax highlighting acts differently on
two OS. I have no idea how to investigate this further.


Recent input:
- f o n t - l o c k - m o SPC <return> M-: C-g ( a 
d d - h o o k SPC ' c - m o d e - h o o k SPC ' t u 
r n - o n - c w a r n - m o d e ) C-j C-x C-f t s t 
/ x . <backspace> <backspace> c w SPC c <return> <escape> 
x c w a r n - m SPC <return> <escape> x <up> <return> 
<help-echo> <help-echo> <down-mouse-1> <mouse-1> <help-echo> 
<help-echo> <menu-bar> <help-menu> <report-emacs-b
ug>

Recent messages:
Loading font-lock...done
Global-Font-Lock mode enabled
list: Quit
Loading cc-mode...done
Loading cwarn...done
Fontifying cwarn.c... (regexps..................)
Loading cwarn...done
Cwarn mode is now off.
Cwarn mode is now on.
Loading emacsbug...done