add test for variadic templates

[[Imported from SVN: r6307]]

m4/Makefile.am

@@ -14,6 +14,7 @@ ALLM4S = 					\
 	cxx0x_compiler.m4			\
 	cxx0x_nullptr.m4			\
 	cxx0x_static_assert.m4			\
+	cxx0x_variadic.m4			\
 	dune.m4					\
 	dune_all.m4				\
 	dune_autobuild.m4			\

m4/cxx0x_variadic.m4

+# tests for C++0x variadic template support
+# the associated macro is called HAVE_VARIADIC_TEMPLATES
+
+AC_DEFUN([VARIADIC_TEMPLATES_CHECK],[
+  AC_REQUIRE([AC_PROG_CXX])
+  AC_REQUIRE([GXX0X])
+  AC_LANG_PUSH([C++])
+  AC_MSG_CHECKING([whether variadic templates are supported])
+  AC_RUN_IFELSE([
+    AC_LANG_PROGRAM([#include<cassert>
+
+      template<typename... T>
+      int addints(T... x);
+
+      int add_ints()
+      {
+        return 0;
+      }
+
+      template<typename T1, typename... T>
+      int add_ints(T1 t1, T... t)
+      {
+        return t1 + add_ints(t...);
+      }], 
+      [
+        assert( 5 == add_ints(9,3,-5,-2) );
+        return 0;
+      ])],[
+    HAVE_VARIADIC_TEMPLATES=yes
+    AC_MSG_RESULT(yes)], [
+    HAVE_VARIADIC_TEMPLATES=no
+    AC_MSG_RESULT(no)])
+  if test "x$HAVE_VARIADIC_TEMPLATES" = xyes; then
+    AC_DEFINE(HAVE_VARIADIC_TEMPLATES, 1, [Define to 1 if nullptr is supported])
+  fi
+  AC_LANG_POP
+])