title: dynamic_cast issue xcode
body: <p>I am working on porting a game from visual studio to xcode the game was completely written in c++ and I am having some troubles with dynamic casting that I never had when running in visual studio. I am wondering if it is a compiler issue or some things are just not supported in the mac environment, any help will be greatly appreciated. Here is a stripped down version of the code that I am running in xcode which will crash when doing the dynamic_cast</p>
  
  <pre><code>class base {
  public:
   int dm;
   virtual void vm(){}
   base(){}
  };
  
  class specific : public base {
  public:
  virtual void vm(){dm++;}
  specific (){}
  };
  
  specific* sp = new specific();
  base* b = (base*) sp;
  specific * s = dynamic_cast&lt; specific * &gt;( b );
  </code></pre>