(mac_draw_string_common, x_per_char_metric)

(mac_draw_string_common, x_per_char_metric)
(mac_compute_glyph_string_overhangs, init_font_name_table)
(XLoadQueryFont, mac_unload_font) [USE_ATSUI]: Add ATSUI support.
(atsu_get_text_layout_with_text_ptr) [USE_ATSUI]: New function.
(x_draw_glyph_string_background)
(x_draw_glyph_string_foreground) [MAC_OS8 && USE_ATSUI]: Don't use
XDrawImageString.  Always draw background and foreground separately.
(x_draw_glyph_string_foreground) [USE_ATSUI]: Don't use 8-bit
functions for one-byte chars when using ATSUI-compatible fonts.
(atsu_font_id_hash) [USE_ATSUI]: New variable.
(syms_of_macterm) [USE_ATSUI]: Initialize and staticpro it.
(XLoadQueryFont): Set min_byte1, max_byte1, min_char_or_byte2, and
max_char_or_byte2 more in detail.
(quit_char_comp, mac_check_for_quit_char) [MAC_OSX]: Remove functions.