(struct font_info): Delete it. Most memnbers go to

(struct font_info): Delete it.  Most memnbers go to
struct font.
(FONT_ENCODING_NOT_DECIDED): Moved to font.h.
(enum FONT_SPEC_INDEX): Delete it.
(font_info, list_fonts_func, load_font_func, query_font_func)
(set_frame_fontset_func, find_ccl_program_func)
(get_font_repertory_func, new_fontset_from_font_name): Delete
externs.
(fontset_from_font_name): Extern it.
(FS_LOAD_FONT, FONT_INFO_ID, FONT_INFO_FROM_ID)
(FONT_INFO_FROM_FACE): Deleted.
(face_for_font): Adjust prototype.