Do return references local statics instead of references to 0 in error cases...

Do return references local statics instead of references to 0 in error cases (was undefined in c++). 
Thx @floriang for reporting at http://irrlicht.sourceforge.net/forum/viewtopic.php?f=7&t=50877



git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@5112 dfc29bdd-3216-0410-991c-e03cc46cb475

source/Irrlicht/CNullDriver.cpp

@@ -1026,7 +1026,11 @@ const SLight& CNullDriver::getDynamicLight(u32 idx) const
 	if ( idx < Lights.size() )
 		return Lights[idx];
 	else
-		return *((SLight*)0);
+	{
+		_IRR_DEBUG_BREAK_IF(true)
+		static const SLight dummy;
+		return dummy;
+	}
 }
 
 

source/Irrlicht/CSceneManager.cpp

@@ -1174,10 +1174,10 @@ void CSceneManager::render()
 //! returns the axis aligned bounding box of this node
 const core::aabbox3d<f32>& CSceneManager::getBoundingBox() const
 {
-	_IRR_DEBUG_BREAK_IF(true) // Bounding Box of Scene Manager wanted.
+	_IRR_DEBUG_BREAK_IF(true) // Bounding Box of Scene Manager should never be used.
 
-	// should never be used.
-	return *((core::aabbox3d<f32>*)0);
+	static const core::aabbox3d<f32> dummy;
+	return dummy;
 }
 
 
@@ -2549,13 +2549,13 @@ IMeshWriter* CSceneManager::createMeshWriter(EMESH_WRITER_TYPE type)
 #else
 		return 0;
 #endif
-	
+
 	case EMWT_B3D:
 #ifdef _IRR_COMPILE_WITH_B3D_WRITER_
 		return new CB3DMeshWriter(FileSystem);
 #else
 		return 0;
-#endif	
+#endif
 	}
 
 	return 0;