* libc/locale/locale.c (lc_ctype_cjk_lang): New static int.
(loadlocale): In case of setting LC_CTYPE, set lc_ctype_cjk_lang
to 1 if the language is "jp", "ko", or "zh", to 0 otherwise.
(__locale_cjk_lang): New function.
* libc/string/local.h (__locale_cjk_lang): Declare.
* libc/string/wcwidth.c: Fix comments.
(__wcwidth): Handle CJK Ambiguous Width characters according
to setting returned by __locale_cjk_lang.