wmemchr
wchar_t *wmemchr(const wchar_t *, wchar_t, size_t);
PROTO_NORMAL(wmemchr);
wchar_t *p = wmemchr(cp, 0, prec);
(cclcompl ? (wmemchr(ccls, (_c), ccle - ccls) == NULL) : \
(wmemchr(ccls, (_c), ccle - ccls) != NULL))
DEF_STRONG(wmemchr);
len = ((wp = wmemchr(wcval->chars, L'\0', (size_t) CCHARW_MAX))