(char_encode_ucs4): New function.

(char_encode_ucs4): New function.
(char_finish_ucs4): New function.
(encode_coding_ucs4): Deleted.
(mule_encode): Use generic encoder for `CODESYS_UCS4'.
(text_encode_generic): Delete local variable `charset' and `half'.
(ucs_to_mule_table): Deleted.
(mule_to_ucs_table): Deleted.
(Fset_ucs_char): Deleted.
(ucs_to_char): Deleted.
(Fucs_char): Deleted.
(Fset_char_ucs): Deleted.
(Fchar_ucs): Deleted.
(decode_ucs4): Deleted.
(mule_char_to_ucs4): Deleted.
(encode_ucs4): Deleted.
(decode_coding_ucs4): Use `DECODE_ADD_UCS_CHAR'.
(decode_coding_utf8): Likewise.
(decode_coding_iso2022): Likewise; don't use `XCHARSET_REP_BYTES'.
(char_encode_iso2022): Fixed.
(syms_of_file_coding): Delete `Fset_ucs_char', `Fucs_char',
`Fset_char_ucs' and `Fchar_ucs'.
(complex_vars_of_file_coding): Don't initialize `ucs_to_mule_table'.