text: typedef unsigned char u_char;
  
  int
  strcasecmp(s1, s2)
  	        const char *s1, *s2;
  {
  	register const u_char
  	*us1 = (const u_char *)s1,
  	*us2 = (const u_char *)s2;
  
  	while (tolower(*us1) == tolower(*us2++))
  		if (*us1++ == '\0')
  			return (0);
  	return (tolower(*us1) - tolower(*--us2));
  }
  