Add ip rule flush capabilty and fix all the prototype changes
because of that code rewrites the nlmsghdr.

(Logical change 1.106)
diff --git a/ip/ipneigh.c b/ip/ipneigh.c
index c3105ef..33e90ad 100644
--- a/ip/ipneigh.c
+++ b/ip/ipneigh.c
@@ -217,7 +217,7 @@
 }
 
 
-int print_neigh(const struct sockaddr_nl *who, const struct nlmsghdr *n, void *arg)
+int print_neigh(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 {
 	FILE *fp = (FILE*)arg;
 	struct ndmsg *r = NLMSG_DATA(n);