(it_props): Delete the entry for Qauto_composed.
(init_iterator): Initialize it->cmp_it.id to -1.
(compute_stop_pos): Call composition_compute_stop_pos.
(face_before_or_after_it_pos): Adjusted for the change of struct
it.
(handle_auto_composed_prop): Delete it.
(handle_composition_prop): Handle only static composition.
(next_overlay_string): Remove it->method == GET_FROM_COMPOSITION
from xassert. Initialize it->cmp_it.stop_pos.
(push_it): Adjusted for the change of struct it.
(pop_it): Likewise.
(get_next_element): Delete next_element_from_composition.
(CHAR_COMPOSED_P): New macro.
(get_next_display_element): For automatic composition, get a face
from the font in the glyph-string.
(set_iterator_to_next): For GET_FROM_BUFFER and GET_FROM_STRING,
check composition by it->cmp_it.id. Delete GET_FROM_COMPOSITION
case.
(next_element_from_string): Check if the character at the current
position is composed by CHAR_COMPOSED_P.
(next_element_from_buffer): Likewise.
(next_element_from_composition): Adjusted for the change of struct
it. Update it->cmp_it.
(dump_glyph): Adjusted for the change of struct glyph.
(fill_composite_glyph_string): Adjusted for the change of struct
it and struct glyph. Don't handle automatic composition here.
(fill_gstring_glyph_string): New function.
(x_get_glyph_overhangs): Handle automatic composition.
(BUILD_COMPOSITE_GLYPH_STRING): Adjusted for the change of struct
glyph.
(BUILD_GSTRING_GLYPH_STRING): New macro.
(BUILD_GLYPH_STRINGS): Call BUILD_GSTRING_GLYPH_STRING for
automatic composition.
(append_composite_glyph): Adjusted for the change of struct it and
struct glyph.
(x_produce_glyphs): Adjusted for the change of struct it.
(check_composition): Delete this function..
(scan_for_column): Handle composition by
composition_compute_stop_pos, composition_reseat_it, and
composition_update_it.
(compute_motion): Likewise.
(Fvertical_motion): Fix checking of composition.
(LGSTRING_XXX, LGLYPH_XXX): These macros moved to composite.h.
(enum lglyph_indices): Likewise.
(font_range): Extern adjusted.
(font_fill_lglyph_metrics): Extern it.
(check_gstring): Use LGSTRING_GLYPH_LEN, not LGSTRING_LENGTH.
(font_prepare_composition): Delete this function.
(font_range): Type and arguments changed.
(Ffont_make_gstring, Ffont_fill_gstring): Delete them.
(font_fill_lglyph_metrics): New function.
(Ffont_shape_text): Renamed to Ffont_shape_gstring and arguments
changed.
(syms_of_font): DEFSYM QCf. Delete defsubr for
Sfont_make_gstring, Sfont_fill_gstring, Sfont_shape_text. Defsubr
Sfont_shape_gstring.
cmp_id.
(struct glyph_string): Delete the member gidx. New members
cmp_id, cmp_from, and cmp_to.
(enum it_method): Delete GET_FROM_COMPOSITION.
(struct composition_it): New struct.
(struct it): New member cmp_it, and iterator_stack_entry.cmp_it.
Delete c, len, cmp_id, cmp_len in u.comp.
