add_crc(buf, l)
void add_crc(buf, l)
add_crc(buf, l)unsigned char *buf;int l;{	unsigned short int u;	u = compute_crc(buf, l);	buf[l] = u&0xff;                /* lsb first */	buf[l+1] = (u>>8)&0xff;         /* msb next */}