newline in multibyte buffer, if previous or next character is a
composite char, check the first component of the composite char.
(while (search-forward "\n" nil t)
(let ((prev (char-before (match-beginning 0)))
(next (following-char)))
+ (if (cmpcharp prev)
+ (setq prev (composite-char-component prev 0)))
+ (if (cmpcharp next)
+ (setq next (composite-char-component next 0)))
(if (and (or (aref (char-category-set next) ?|)
(aref (char-category-set prev) ?|))
(or (get-charset-property (char-charset prev)