dnl Available from the GNU Autoconf Macro Archive at:
dnl http://www.gnu.org/software/ac-archive/htmldoc/ac_cxx_have_sstream.html
dnl
AC_DEFUN([AC_CXX_HAVE_SSTREAM],
[AC_CACHE_CHECK(whether the compiler has stringstream,
ac_cv_cxx_have_sstream,
[AC_REQUIRE([AC_CXX_NAMESPACES])
 AC_LANG_SAVE
 AC_LANG_CPLUSPLUS
 AC_TRY_COMPILE([#include <sstream>
#ifdef HAVE_NAMESPACES
using namespace std;
#endif],[stringstream message; message << "Hello"; return 0;],
 ac_cv_cxx_have_sstream=yes, ac_cv_cxx_have_sstream=no)
 AC_LANG_RESTORE
])
if test "$ac_cv_cxx_have_sstream" = yes; then
  AC_DEFINE(HAVE_SSTREAM,,[define if the compiler has stringstream])
fi
])
dnl Available from the GNU Autoconf Macro Archive at:
dnl http://www.gnu.org/software/ac-archive/htmldoc/ac_cxx_namespaces.html
dnl
AC_DEFUN([AC_CXX_NAMESPACES],
[AC_CACHE_CHECK(whether the compiler implements namespaces,
ac_cv_cxx_namespaces,
[AC_LANG_SAVE
 AC_LANG_CPLUSPLUS
 AC_TRY_COMPILE([namespace Outer { namespace Inner { int i = 0; }}],
                [using namespace Outer::Inner; return i;],
 ac_cv_cxx_namespaces=yes, ac_cv_cxx_namespaces=no)
 AC_LANG_RESTORE
])
if test "$ac_cv_cxx_namespaces" = yes; then
  AC_DEFINE(HAVE_NAMESPACES,,[define if the compiler implements namespaces])
fi
])