bug#35468: [PATCH] Refactor draw_glyph_string on X and w32

[mituharu]

> Because of the reasons I mentioned above, I'd prefer
> erase_rectangle to fill_rectangle_with_color/stipple.  Also, many
> use cases in the Mac port involve erasure of multiple rectangles,
> so erase_rectangles (multi-rectangle version like
> XFillRectangles) would eliminate some overhead of setting up
> colors and the clipping area.

Sorry, there weren't so many occurrence of multi-rectangle
filling/erasing.  Maybe I counted them wrong previously.

                                     YAMAMOTO Mitsuharu
                                mituharu@math.s.chiba-u.ac.jp