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/ignore_template_constructor.i

@@ -17,9 +17,10 @@
 #if defined(SWIG_GOOD_VECTOR)
 %inline %{
 class Flow {
-  Flow() {}
+double x;
+ Flow():x(0.0) {}
 public:
-  Flow(double d) {}
+ Flow(double d) : x(d) {}
 };
 %}
 
@@ -28,9 +29,10 @@ public:
 
 %inline %{
 class Flow {
+double x;
 public:
-  Flow() {}
-  Flow(double d) {}
+ Flow(): x(0.0) {}
+ Flow(double d) : x(d) {}
 };
 %}