fixing #1772

livesupport/src/modules/gstreamerElements/etc/acinclude.m4

@@ -89,6 +89,31 @@ AC_DEFUN([PKG_CHECK_MODULES], [
 ])
 
 
+dnl-----------------------------------------------------------------------------
+dnl Macro to check for C++ namespaces
+dnl for more information on this macro, see
+dnl http://autoconf-archive.cryp.to/ac_cxx_namespaces.html
+dnl
+dnl usage:
+dnl  If the compiler can prevent names clashes using namespaces,
+dnl  define HAVE_NAMESPACES.
+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
+])
+
+
 dnl-----------------------------------------------------------------------------
 dnl Macro to check for the boost datetime library.
 dnl for more information on boost, see http://www.boost.org/