Set SO_REUSEADDR to ensure that portmap can restart properly.

https://bugs.launchpad.net/ubuntu/+source/portmap/+bug/688550

===================================================================
--- portmap-6.0.0.orig/portmap.c	2011-03-16 20:43:26.000000000 +0100
+++ portmap-6.0.0/portmap.c	2011-03-17 07:30:17.000000000 +0100
@@ -142,9 +142,9 @@
   * loopback interface address.
   */
 
+static int on = 1;
 #ifdef LOOPBACK_SETUNSET
 static SVCXPRT *ludpxprt, *ltcpxprt;
-static int on = 1;
 #ifndef INADDR_LOOPBACK
 #define INADDR_LOOPBACK ntohl(inet_addr("127.0.0.1"))
 #endif
@@ -399,9 +399,7 @@
 		syslog(LOG_ERR, "cannot create udp socket: %m");
 		exit(1);
 	}
-#ifdef LOOPBACK_SETUNSET
 	setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof on);
-#endif
 
 	memset((char *) &addr, 0, sizeof(addr));
 	addr.sin_addr.s_addr = 0;
@@ -434,9 +432,7 @@
 		syslog(LOG_ERR, "cannot create tcp socket: %m");
 		exit(1);
 	}
-#ifdef LOOPBACK_SETUNSET
 	setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof on);
-#endif
 	if (bind(sock, (struct sockaddr *)&addr, len) != 0) {
 		syslog(LOG_ERR, "cannot bind tcp: %m");
 		exit(1);