This adds in the GYP files needed for our GYP build.

core/cross/types.h

Index: core/cross/types.h
===================================================================
--- core/cross/types.h	(revision 19090)
+++ core/cross/types.h	(working copy)
@@ -105,6 +105,30 @@
 // We can add more sophisticated per-platform #defines as necessary here
 #define IS_LITTLE_ENDIAN 1
 
+// When you upcast (that is, cast a pointer from type Foo to type
+// SuperclassOfFoo), it's fine to use implicit_cast<>, since upcasts
+// always succeed.  When you downcast (that is, cast a pointer from
+// type Foo to type SubclassOfFoo), static_cast<> isn't safe, because
+// how do you know the pointer is really of type SubclassOfFoo?  It
+// could be a bare Foo, or of type DifferentSubclassOfFoo.  Thus, when
+// you downcast, you should use this macro.  We used to do a
+// dynamic_cast there in debug mode just to make sure it was the right
+// type, but now that RTTI is completely turned off, we just do the
+// implicit_cast compile-time check.
+
+template<typename To, typename From>     // use like this: down_cast<T*>(foo);
+inline To down_cast(From* f) {                   // so we only accept pointers
+  // Ensures that To is a sub-type of From *.  This test is here only
+  // for compile-time type checking, and has no overhead in an
+  // optimized build at run-time, as it will be optimized away
+  // completely.
+  if (false) {
+    implicit_cast<From*, To>(0);
+  }
+
+  return static_cast<To>(f);
+}
+
 namespace o3d {
 
 // String