add modelines to .hxx files as well

mysqlc/source/mysqlc_databasemetadata.hxx

@@ -1,3 +1,4 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /*************************************************************************
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
@@ -239,3 +240,5 @@ namespace connectivity
 }
 
 #endif // CONNECTIVITY_SDATABASEMETADATA_HXX
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */