* libc/string/local.h: New file.

	* libc/string/local.h: New file.
	* libc/string/wcswidth.c (wcswidth):  Convert japanese wide
	characters to Unicode here.  Handle surrogate pairs for UTF-16
	systems.  Call __wcwidth rather than wcwidth.
	* libc/string/wcwidth.c: New implementation using Markus Kuhn's
	wcwidth implementation for Unicode.
	(bisearch): New static function.
	(__wcwidth): New function.  Take wint_t rather than wchar_t as
	parameter to allow full Unicode handling on UTF-16 systems.
	Move old wcwidth implementation here for non-multibyte aware
	systems.
	(wcwidth): Convert japanese wide characters to Unicode here.
	Call __wcwidth rather than using iswprint/iswcntrl.