_tolower
ch = _tolower(ch);
extern int _tolower(int);
ch = _tolower((int)ch);
ch = _tolower(ch);
#define TOLOWER(c) (isascii(c) && isupper(c) ? _tolower(c) : c)
#define LOWER(c) (isupper((c)) ? _tolower((c)) : (c))
*ap = _tolower(*ap);
*mung = _tolower(c);
*mung = _tolower(c);
if (*fmt == 'h' || _tolower(*fmt) == 'l' ||
_tolower(*fmt) == 'z' || *fmt == 't') {
} else if (_tolower(qualifier) == 'z') {
old_fmt[-2] == '0' && _tolower(old_fmt[-1]) == 'x';