Update BIG5-HKSCS charmap to HKSCS-2008

Update BIG5-HKSCS charmap to HKSCS-2008

	[BZ #14991]
	* charmaps/BIG5-HKSCS: Update to HKSCS-2008.

	[BZ #14991]
	* iconvdata/big5hkscs.c (big5hkscs_to_ucs, from_ucs4)
	(from_ucs4_idx): Regenerate.
	(MIN_NEEDED_FROM, MAX_NEEDED_FROM, MIN_NEEDED_TO): Remove macros.
	(FROM_LOOP_MIN_NEEDED_FROM, FROM_LOOP_MAX_NEEDED_FROM)
	(FROM_LOOP_MIN_NEEDED_TO, FROM_LOOP_MAX_NEEDED_TO)
	(TO_LOOP_MIN_NEEDED_FROM, TO_LOOP_MAX_NEEDED_FROM)
	(TO_LOOP_MIN_NEEDED_TO, TO_LOOP_MAX_NEEDED_TO, PREPARE_LOOP)
	(EXTRA_LOOP_ARGS, SAVE_RESET_STATE, EMIT_SHIFT_TO_INIT)
	(EXTRA_LOOP_DECLS, MAX_NEEDED_OUTPUT): New macros.
	(MIN_NEEDED_INPUT, MAX_NEEDED_INPUT, MIN_NEEDED_OUTPUT): Define
	from FROM_LOOP and TO_LOOP specific macros.
	(BODY): Handle combining characters.
	* iconvdata/BIG5HKSCS.irreversible: Update.
	* iconvdata/BIG5HKSCS.precomposed: New file.
	* iconvdata/testdata/BIG5HKSCS: Add all characters from range
	0x8740 - 0x87DF.
	* iconvdata/testdata/BIG5HKSCS..UTF8: Update.