being used, call isearch-process-search-multibyte-characters.
(if (and enable-multibyte-characters
(>= char ?\200)
(<= char ?\377))
- (isearch-process-search-char (unibyte-char-to-multibyte char))
+ (if (keyboard-coding-system)
+ (isearch-process-search-multibyte-characters char)
+ (isearch-process-search-char (unibyte-char-to-multibyte char)))
(if current-input-method
(isearch-process-search-multibyte-characters char)
(isearch-process-search-char char)))))