include: Update the MIDL_STUB_MESSAGE structure.

Reduce the size of the IsClient field, as is done in the latest SDKs
to fix NdrClientInitializeNew tests on XP SP3 and Win2003+.
diff --git a/include/rpcndr.h b/include/rpcndr.h
index 7938529..a0968d5 100644
--- a/include/rpcndr.h
+++ b/include/rpcndr.h
@@ -175,7 +175,9 @@
   ULONG BufferLength;
   ULONG MemorySize;
   unsigned char *Memory;
-  int IsClient;
+  unsigned char IsClient;
+  unsigned char Pad;
+  unsigned short uFlags2;
   int ReuseBuffer;
   struct NDR_ALLOC_ALL_NODES_CONTEXT *pAllocAllNodesContext;
   struct NDR_POINTER_QUEUE_STATE *pPointerQueueState;