* cm.c (calccost, cmgoto): Use const pointers where appropriate.

* cm.c (calccost, cmgoto): Use const pointers where appropriate.

* cm.h (struct cm): Likewise.
* dispextern.h (do_line_insertion_deletion_costs): Likewise.
* scroll.c (ins_del_costs, do_line_insertion_deletion_costs): Likewise.
* term.c (tty_ins_del_lines, calculate_costs, struct fkey_table):
(term_get_fkeys_1, append_glyphless_glyph, produce_glyphless_glyph):
(turn_on_face, init_tty): Likewise.
* termchar.h (struct tty_display_info): Likewise.
* term.c (tgetflag, tgetnum, tgetstr): Redefine to use const pointers.