mksysinfo, net: Always define syscall.SO_REUSEPORT.

From-SVN: r186857

libgo/go/net/sockopt_bsd.go

@@ -53,9 +53,11 @@ func setDefaultMulticastSockopts(s int) error {
 	// This option is supported only in descendants of 4.4BSD,
 	// to make an effective multicast application that requires
 	// quick draw possible.
-	err = syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEPORT, 1)
-	if err != nil {
-		return os.NewSyscallError("setsockopt", err)
+	if syscall.SO_REUSEPORT != 0 {
+		err = syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEPORT, 1)
+		if err != nil {
+			return os.NewSyscallError("setsockopt", err)
+		}
 	}
 	return nil
 }

libgo/mksysinfo.sh

@@ -264,7 +264,7 @@ grep '^const _SHUT_' gen-sysinfo.go |
   sed -e 's/^\(const \)_\(SHUT[^= ]*\)\(.*\)$/\1\2 = _\2/' >> ${OUT}
 
 # The net package requires some const definitions.
-for m in IP_PKTINFO IPV6_V6ONLY IPPROTO_IPV6 IPV6_JOIN_GROUP IPV6_LEAVE_GROUP IPV6_TCLASS; do
+for m in IP_PKTINFO IPV6_V6ONLY IPPROTO_IPV6 IPV6_JOIN_GROUP IPV6_LEAVE_GROUP IPV6_TCLASS SO_REUSEPORT; do
   if ! grep "^const $m " ${OUT} >/dev/null 2>&1; then
     echo "const $m = 0" >> ${OUT}
   fi