Fix failure when -fno-rtti test is run in C++17 or later

	* testsuite/util/testsuite_allocator.h (__gnu_test::memory_resource):
	Only define when RTTI is enabled.

From-SVN: r263820

libstdc++-v3/ChangeLog

 2018-08-23  Jonathan Wakely  <jwakely@redhat.com>
 
+	* testsuite/util/testsuite_allocator.h (__gnu_test::memory_resource):
+	Only define when RTTI is enabled.
+
 	* include/debug/vector (__niter_base): Define for C++98.
 
 	* testsuite/25_algorithms/partial_sort_copy/debug/irreflexive_neg.cc:

libstdc++-v3/testsuite/util/testsuite_allocator.h

@@ -697,7 +697,8 @@ namespace __gnu_test
     };
 #endif // C++11
 
-#if __cplusplus >= 201703L && __cpp_aligned_new
+#if __cplusplus >= 201703L
+#if __cpp_aligned_new && __cpp_rtti
     // A concrete memory_resource, with error checking.
     class memory_resource : public std::pmr::memory_resource
     {
@@ -835,6 +836,7 @@ namespace __gnu_test
 
       allocation_lists* lists;
     };
+#endif // aligned-new && rtti
 
     // Set the default resource, and restore the previous one on destruction.
     struct default_resource_mgr
@@ -849,7 +851,7 @@ namespace __gnu_test
       std::pmr::memory_resource* prev;
     };
 
-#endif // C++17 && aligned-new
+#endif // C++17
 
 } // namespace __gnu_test