introduce setsockopt_reuseaddr(int fd), setsockopt_broadcast(int fd),
use them where appropriate. 200 bytes saved

diff --git a/networking/ping6.c b/networking/ping6.c
index 6ab9ce0..9f0509e 100644
--- a/networking/ping6.c
+++ b/networking/ping6.c
@@ -356,9 +356,7 @@
 #endif /*ICMP6_FILTER*/
 
 	/* enable broadcast pings */
-	sockopt = 1;
-	setsockopt(pingsock, SOL_SOCKET, SO_BROADCAST, (char *) &sockopt,
-			   sizeof(sockopt));
+	setsockopt_broadcast(pingsock);
 
 	/* set recv buf for broadcast pings */
 	sockopt = 48 * 1024;