diff --git a/src/pkg/syscall/net_nacl.go b/src/pkg/syscall/net_nacl.go
index f6d9e20f644..a2588d04191 100644
--- a/src/pkg/syscall/net_nacl.go
+++ b/src/pkg/syscall/net_nacl.go
@@ -112,6 +112,7 @@ const (
 	SO_SNDBUF
 	SO_KEEPALIVE
 	SO_LINGER
+	SO_ERROR
 	IP_MULTICAST_IF
 	IP_MULTICAST_LOOP
 	IP_ADD_MEMBERSHIP