--- /dev/null
+dnl Copyright (C) 2007-2016 CEA/DEN, EDF R&D, OPEN CASCADE
+dnl
+dnl Copyright (C) 2003-2007 OPEN CASCADE, EADS/CCR, LIP6, CEA/DEN,
+dnl CEDRAT, EDF R&D, LEG, PRINCIPIA R&D, BUREAU VERITAS
+dnl
+dnl This library is free software; you can redistribute it and/or
+dnl modify it under the terms of the GNU Lesser General Public
+dnl License as published by the Free Software Foundation; either
+dnl version 2.1 of the License, or (at your option) any later version.
+dnl
+dnl This library is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+dnl Lesser General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU Lesser General Public
+dnl License along with this library; if not, write to the Free Software
+dnl Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+dnl
+dnl See http://www.salome-platform.org/ or email : webmaster.salome@opencascade.com
+dnl
+
+dnl @synopsis AC_CXX_NAMESPACES
+dnl If the compiler can prevent names clashes using namespaces, define
+dnl HAVE_NAMESPACES.
+dnl @version $Id$
+dnl @author Luc Maisonobe
+dnl
+AC_DEFUN([AC_CXX_NAMESPACES],
+[AC_CACHE_CHECK(whether the compiler implements namespaces,
+ac_cv_cxx_namespaces,
+[AC_LANG_SAVE
+ AC_LANG_CPLUSPLUS
+ AC_TRY_COMPILE([namespace Outer { namespace Inner { int i = 0; }}],
+ [using namespace Outer::Inner; return i;],
+ ac_cv_cxx_namespaces=yes, ac_cv_cxx_namespaces=no)
+ AC_LANG_RESTORE
+])
+if test "$ac_cv_cxx_namespaces" = yes; then
+ AC_DEFINE(HAVE_NAMESPACES,,[define if the compiler implements namespaces])
+fi
+])