Microsoft com vtable compatibility workaround for g++.  Basically adds
an optional 8 bytes padding to COM objects where the RTTI would be.

diff --git a/graphics/d3dexecutebuffer.c b/graphics/d3dexecutebuffer.c
index 7db3e23..2bb00e0 100644
--- a/graphics/d3dexecutebuffer.c
+++ b/graphics/d3dexecutebuffer.c
@@ -843,7 +843,9 @@
 /*******************************************************************************
  *				IDirect3DLight VTable
  */
-static ICOM_VTABLE(IDirect3DExecuteBuffer) executebuffer_vtable = {
+static ICOM_VTABLE(IDirect3DExecuteBuffer) executebuffer_vtable = 
+{
+  ICOM_MSVTABLE_COMPAT_DummyRTTIVALUE
   /*** IUnknown methods ***/
   IDirect3DExecuteBufferImpl_QueryInterface,
   IDirect3DExecuteBufferImpl_AddRef,