c1 = tolower (*p1++); c2 = tolower (*p2++);
c1 = TOLOWER (*p1++); c2 = TOLOWER (*p2++);
__strcasecmp (s1, s2)     const char *s1;     const char *s2;{  const unsigned char *p1 = (const unsigned char *) s1;  const unsigned char *p2 = (const unsigned char *) s2;  unsigned char c1, c2;  if (p1 == p2)    return 0;  do    {      c1 = tolower (*p1++);      c2 = tolower (*p2++);      if (c1 == '\0')	break;    }  while (c1 == c2);  return c1 - c2;}