ping6: err() when setsockopts fail

[David Gwynne]

this good idea was suggested by kn@ and deraadt@

ok?

Index: ping.c
===================================================================
RCS file: /cvs/src/sbin/ping/ping.c,v
retrieving revision 1.232
diff -u -p -r1.232 ping.c
--- ping.c      10 Nov 2018 23:44:53 -0000      1.232
+++ ping.c      10 Nov 2018 23:47:05 -0000
@@ -678,23 +678,23 @@ main(int argc, char *argv[])
                        optval = tos;
                        if (setsockopt(s, IPPROTO_IPV6, IPV6_TCLASS, &optval,
                            (socklen_t)sizeof(optval)) < 0)
-                               warn("setsockopt(IPV6_TVAL)"); /* XXX err? */
+                               err(1, "setsockopt(IPV6_TCLASS)");
                }
 
                if (df) {
                        optval = 1;
                        if (setsockopt(s, IPPROTO_IPV6, IPV6_DONTFRAG,
                            &optval, (socklen_t)sizeof(optval)) < 0)
-                               warn("setsockopt(IPV6_DONTFRAG"); /* err? */
+                               err(1, "setsockopt(IPV6_DONTFRAG)");
                }
 
                optval = 1;
                if (setsockopt(s, IPPROTO_IPV6, IPV6_RECVPKTINFO, &optval,
                    (socklen_t)sizeof(optval)) < 0)
-                       warn("setsockopt(IPV6_RECVPKTINFO)"); /* XXX err? */
+                       err(1, "setsockopt(IPV6_RECVPKTINFO)");
                if (setsockopt(s, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &optval,
                    (socklen_t)sizeof(optval)) < 0)
-                       warn("setsockopt(IPV6_RECVHOPLIMIT)"); /* XXX err? */
+                       err(1, "setsockopt(IPV6_RECVHOPLIMIT)");
        } else {
                u_char loop = 0;