(CATEGORY_MASK_RAW_TEXT): New macro.

(CATEGORY_MASK_RAW_TEXT): New macro.
(detect_coding_utf_8, detect_coding_utf_16)
(detect_coding_emacs_mule, detect_coding_iso_2022)
(detect_coding_sjis, detect_coding_big5)
(detect_coding_ccl, detect_coding_charset): Change argument MASK
to DETECT_INFO.  Update DETECT_INFO and return 1 if the byte
sequence is valid in this coding system.  Callers changed.
(MAX_ANNOTATION_LENGTH): New macro.
(ADD_ANNOTATION_DATA): New macro.
(ADD_COMPOSITION_DATA): Argument changed.  Callers changed.  Call
ADD_ANNOTATION_DATA.  The format of annotation data changed.
(ADD_CHARSET_DATA): New macro.
(emacs_mule_char): New argument ID.  Callers changed.
(decode_coding_emacs_mule, decode_coding_iso_2022)
(decode_coding_sjis, decode_coding_big5, decode_coding_charset):
Produce charset annotation data in coding->charbuf.
(encode_coding_emacs_mule, encode_coding_iso_2022): Pay attention
to charset annotation data in coding->charbuf.
(setup_coding_system): Add CODING_ANNOTATE_CHARSET_MASK
coding->common_flags if the coding system is iso-2022 based and
uses designation.
(produce_composition): Adjusted for the new annotation data
format.
(produce_charset): New function.
(produce_annotation): Handle charset annotation.
(handle_composition_annotation, handle_charset_annotation): New
functions.
(consume_chars): Handle charset annotation.  Utilize the above two
functions.
(encode_coding_object): If SRC_OBJECT and DST_OBJECT are the same
buffer, get the deleted text as a string and set
coding->src_object to that string.
(detect_coding, detect_coding_system): Use the new struct
coding_detection_info.