Introduce OPM_UNUSED as a portable wrapper to __attribute__((unused))

This works pretty much the same way as DUNE_DEPRECATED (without message).

Thanks to Elias Pipping for implementing this.

dune-common SVN revision: r6556

opm/core/Unused.hpp

@@ -0,0 +1,28 @@
+// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+// vi: set et ts=4 sw=4 sts=4:
+/*****************************************************************************
+ *   Copyright (C) 2010-2013 by Andreas Lauser                               *
+ *                                                                           *
+ *   This program is free software: you can redistribute it and/or modify    *
+ *   it under the terms of the GNU General Public License as published by    *
+ *   the Free Software Foundation, either version 2 of the License, or       *
+ *   (at your option) any later version.                                     *
+ *                                                                           *
+ *   This program is distributed in the hope that it will be useful,         *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of          *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           *
+ *   GNU General Public License for more details.                            *
+ *                                                                           *
+ *   You should have received a copy of the GNU General Public License       *
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>.   *
+ *****************************************************************************/
+#ifndef OPM_CORE_UNUSED_HH
+#define OPM_CORE_UNUSED_HH
+
+#ifndef HAS_ATTRIBUTE_UNUSED
+#define OPM_UNUSED
+#else
+#define OPM_UNUSED __attribute__((unused))
+#endif
+
+#endif