Workaround for clang 3.2 libc++ empty struct bug.

Certain tests have empty structs or classes.
This encounters a bug with clang: http://llvm.org/bugs/show_bug.cgi?id=16764
This is fixed in later versions of clang, but not the version
currently bundled with Mavericks and XCode 5

Examples/test-suite/constructor_copy.i

@@ -94,14 +94,16 @@ public:
 
 namespace Space {
 class Flow {
+int x;
 public:
-  Flow(int i) {}
+ Flow(int i) : x(i) {}
 };
 
 
 class FlowFlow {
+int x;
 public:
-  FlowFlow(int i) {}
+ FlowFlow(int i) : x(i) {}
 };
 
 }