bug#5730: 23.1.94; Emacs crash running gnus on Windows

[Chong Yidong]

I've checked a change into the bzr branch; could you verify if it fixes
the problem?  If it's inconvenient for you to check out the bzr branch,
try the patch below:

*** xdisp.c     2010-03-10 21:20:33.000000000 -0500
--- xdisp.c     2010-03-24 17:22:37.000000000 -0400
***************
*** 1375,1407 ****
        visible_p = 1;
        if (visible_p)
        {
!         if (it_method == GET_FROM_BUFFER)
!           {
!             Lisp_Object window, prop;
! 
!             XSETWINDOW (window, w);
!             prop = Fget_char_property (make_number (charpos),
!                                        Qinvisible, window);
! 
!             /* If charpos coincides with invisible text covered with an
!                ellipsis, use the first glyph of the ellipsis to compute
!                the pixel positions.  */
!             if (TEXT_PROP_MEANS_INVISIBLE (prop) == 2)
!               {
!                 struct glyph_row *row = it.glyph_row;
!                 struct glyph *glyph = row->glyphs[TEXT_AREA];
!                 struct glyph *end = glyph + row->used[TEXT_AREA];
!                 int x = row->x;
! 
!                 for (; glyph < end
!                        && (!BUFFERP (glyph->object)
!                            || glyph->charpos < charpos);
!                      glyph++)
!                   x += glyph->pixel_width;
!                 top_x = x;
!               }
!           }
!         else if (it_method == GET_FROM_DISPLAY_VECTOR)
            {
              /* We stopped on the last glyph of a display vector.
                 Try and recompute.  Hack alert!  */
--- 1375,1381 ----
        visible_p = 1;
        if (visible_p)
        {
!         if (it_method == GET_FROM_DISPLAY_VECTOR)
            {
              /* We stopped on the last glyph of a display vector.
                 Try and recompute.  Hack alert!  */