add comments about warnings

ospfd/ospf_network.c

@@ -154,6 +154,10 @@ int
 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) )

ospfd/ospf_opaque.c

@@ -223,6 +223,7 @@ ospf_opaque_type_name (u_char opaque_type)
     default:
       if (OPAQUE_TYPE_RANGE_UNASSIGNED (opaque_type))
         name = "Unassigned";
+      /* XXX warning: comparison is always true due to limited range of data type */
       else if (OPAQUE_TYPE_RANGE_RESERVED (opaque_type))
         name = "Private/Experimental";
       break;