Make __builtin_launder test code C++03.

test/boost_has_builtin_launder.ipp

@@ -12,18 +12,21 @@
 #include <new>
 
 namespace boost_has_builtin_launder {
-
+//
+// This is intensionally C++03 code as __builtin_launder can be used even when std::launder
+// isn't available (ie pre-C++17).
 struct X
 {
     const int const_int;
-    X() = delete;
+    X() : const_int(0) {};
     X(const int i) : const_int(i) {}
+    X(const X& o) : const_int(o.const_int) {};
 };
 
 int test()
 {
-    X original{1};
-    new (&original) X{2}; //Overwrite X
+    X original(1);
+    new (&original) X(2); //Overwrite X
     return __builtin_launder(&original)->const_int == 2 ? 0 : -1; //After laundering, new value should be returned
 }