+static int s = -1; /* socket used for communications */
+static struct sockaddr no_addr;
+
+
+#ifndef FD_SET
+#define NFDBITS 32
+#define FD_SETSIZE 32
+#define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
+#define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
+#define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
+#define FD_ZERO(p) bzero((char *)(p), sizeof(*(p)))
+#endif
+