Fix C++03

Author: H-G-Hristov

libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/common.h

@@ -39,13 +39,14 @@ struct A {
   A& operator=(const A&);
 };
 
-class Abstract
-{
-    virtual ~Abstract() = 0;
+class Abstract {
+  virtual ~Abstract() = 0;
 };
 
 // Types for reference_{constructs/converts}_from_temporary
 
+#if TEST_STD_VER >= 23
+
 struct NonPOD {
   NonPOD(int);
 };
@@ -83,4 +84,6 @@ class ExplicitConversionRef {
   explicit operator int&();
 };
 
+#endif
+
 #endif // TEST_META_UNARY_COMP_COMMON_H