Drop OASIS warning about ghost cells and print a DEF reader warning if a foreign cell cannot be substituted

src/plugins/streamers/lefdef/db_plugin/dbLEFDEFPlugin.cc

@@ -276,6 +276,14 @@ LEFDEFReader::read_lefdef (db::Layout &layout, const db::LoadLayoutOptions &opti
 
     }
 
+    //  Warn about cells that could not be resolved
+    for (std::map<std::string, db::cell_index_type>::iterator f = foreign_cells.begin (); f != foreign_cells.end (); ++f) {
+      if (f->second != seen) {
+        importer.warn (tl::sprintf (tl::to_string (tr ("Could not find a substitution layout for foreign cell '%s'")),
+                                    f->first));
+      }
+    }
+
   }
 
   state.finish (layout);

src/plugins/streamers/oasis/db_plugin/dbOASISWriter.cc

@@ -1671,7 +1671,6 @@ OASISWriter::write (db::Layout &layout, tl::OutputStream &stream, const db::Save
 
     //  skip cell body if the cell is not to be written
     if (skip_cell_body (cref)) {
-      tl::warn << tl::to_string (tr ("Cannot write ghost cell to OASIS - skipping cell: ")) << layout.cell_name (*cell);
       continue;
     }