(byte_table_description): Use `XD_LISP_OBJECT_ARRAY' instead of
`XD_LISP_OBJECT'.
(char_id_table_description): Delete bogus `, 1'.
(Fget_char_attribute): Refer encoding_table of each coded-charset to
get value of coded-charset attribute of a character.
(Fput_char_attribute): Use `make_older_vector' instead of
`make_vector'; use encoding_table of each coded-charset to store value
of coded-charset attribute of a character.
(Fremove_char_attribute): Use encoding_table of each coded-charset to
store value of coded-charset attribute of a character.
(mark_charset): Mark `cs->encoding_table'; don't mark
`cs->decoding_table'.
(charset_description): Add description of new member `encoding_table'.
(make_charset): Initialize `encoding_table'.