(store_frame_title, string_char_and_length):

(store_frame_title, string_char_and_length):
(message_dolog, message2, message2_nolog, set_message): String
pointer args now point to const.
(set_message_1): Cast message string argument to const pointer.
(string_pos_nchars_ahead, init_from_display_pos):
(face_before_or_after_it_pos, next_element_from_string):
(get_overlay_arrow_glyph_row, display_mode_element):
(decode_mode_spec_coding): Use const for pointer to lisp string
data.