The xfont backend using XChar2b in its API doesn't mean that we should
use it everywhere else.
* src/dispextern.h (glyph_string):
* src/ftcrfont.c (ftcrfont_draw):
* src/ftxfont.c (ftxfont_draw):
* src/w32term.c (w32_draw_glyphless_glyph_string_foreground):
* src/xdisp.c (init_glyph_string, get_char_face_and_encoding)
(get_glyph_face_and_encoding, get_char_glyph_code)
(fill_gstring_glyph_string, fill_stretch_glyph_string)
(normal_char_ascent_descent, gui_get_glyph_overhangs)
(compute_overhangs_and_x, gui_produce_glyphs):
* src/xfont.c (xfont_get_pcm, xfont_chars_supported, xfont_open)
(xfont_encode_char, xfont_text_extents, xfont_draw)
* src/xftfont.c (xftfont_draw):
* src/xterm.c (x_compute_glyph_string_overhangs)
(x_draw_glyphless_glyph_string_foreground): Use unsigned over XChar2b.
* src/nsgui.h:
* src/w32gui.h:
* src/xterm.h: Remove XChar2b, STORE_XCHAR2B, XCHAR2B_BYTE1, and
XCHAR2B_BYTE2 typedefs and macros.
* src/font.h (font_driver):
(ftfont_text_extents)
* src/ftcrfont.c (ftcrfont_text_extents):
* src/ftfont.c (ftfont_text_extents):
* src/macfont.m (macfont_text_extents):
* src/nsfont.m (nsfont_text_extents):
* src/w32font.h (w32_font_text_extents):
* src/font.c (xfont_text_extents):
* src/xftfont.c (xftfont_text_extents): Make code parameter const.