Added depends_on template and usage in RenderBin to help with static variable destruction ordering

include/osg/Referenced

@@ -31,6 +31,13 @@ namespace osg {
 class DeleteHandler;
 class Observer;
 
+/** template class to help enforce static initialization order. */
+template <typename T, T M()>
+struct depends_on
+{
+    depends_on() { M(); }
+};
+
 /** Base class from providing referencing counted objects.*/
 class OSG_EXPORT Referenced
 {

src/osgUtil/RenderBin.cpp

@@ -26,8 +26,8 @@
 using namespace osg;
 using namespace osgUtil;
 
-
-class RenderBinPrototypeList : public osg::Referenced, public std::map< std::string, osg::ref_ptr<RenderBin> > 
+class RenderBinPrototypeList : osg::depends_on<OpenThreads::Mutex*, osg::Referenced::getGlobalReferencedMutex>,
+                               public osg::Referenced, public std::map< std::string, osg::ref_ptr<RenderBin> >
 {
     public:
         RenderBinPrototypeList() {}