build: check for linux/genetlink.h

Change-Id: Id18fcc81a49e769a05c4416cdce03022a2179051
Refs: #4020
diff --git a/src/net/detail/netlink-message.hpp b/src/net/detail/netlink-message.hpp
index 3908d4e..498bd24 100644
--- a/src/net/detail/netlink-message.hpp
+++ b/src/net/detail/netlink-message.hpp
@@ -27,7 +27,7 @@
 #include "../../common.hpp"
 #include "../ethernet.hpp"
 
-#ifndef NDN_CXX_HAVE_RTNETLINK
+#ifndef NDN_CXX_HAVE_NETLINK
 #error "This file should not be included ..."
 #endif