add comments about warnings
diff --git a/ospfd/ospf_network.c b/ospfd/ospf_network.c
index 7d5b730..a8d5168 100644
--- a/ospfd/ospf_network.c
+++ b/ospfd/ospf_network.c
@@ -154,6 +154,10 @@
 ospf_sock_init (void)
 {
   int ospf_sock;
+  /*
+   * XXX warning: unused variable `tos'
+   * tos should be ifdefed similarly to usage
+   */
   int ret, tos, hincl = 1;
 
   if ( ospfd_privs.change (ZPRIVS_RAISE) )