TOLOWER
char c1 = TOLOWER(*s1);
char c2 = TOLOWER(*s2);
c = TOLOWER(c);
if (!ISALPHA(c) || (TOLOWER(c) != 'o' && TOLOWER(c) != 'i')) {
*out = (TOLOWER(c) == 'o') ? 1 : 0;
table[TOLOWER(*patend)] = 1;
|| TOLOWER(*s) == cc
&& TOLOWER(*q) != *p
define TOLOWER(ch) tolower(ch)
*p = TOLOWER(*p);