Cleanup some compiler warnings under CentOS 5.5

This patch cleans up a couple of warnings when compiling on CentOS 5.5
using gcc 4.1.2.

vvp/event.h

@@ -1,7 +1,7 @@
 #ifndef __event_H
 #define __event_H
 /*
- * Copyright (c) 2004-2009 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2004-2010 Stephen Williams (steve@icarus.com)
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -122,6 +122,7 @@ struct waitable_hooks_s {
 
     public:
       waitable_hooks_s() : event_ctls(0) { last = &event_ctls; }
+      virtual ~waitable_hooks_s() {}
 
       virtual vthread_t add_waiting_thread(vthread_t thread) = 0;
 
@@ -138,7 +139,7 @@ struct waitable_hooks_s {
  * needed is the list of threads waiting on that instance.
  */
 struct waitable_state_s {
-      waitable_state_s() : threads(0) { }
+      waitable_state_s() : threads(0) {}
 
       vthread_t threads;
 };

vvp/ufunc.cc

@@ -52,7 +52,10 @@ ufunc_core::ufunc_core(unsigned owid, vvp_net_t*ptr,
 
       functor_ref_lookup(&result_, result_label);
 
-      compile_vpi_lookup((vpiHandle*)(&func_scope_), scope_label);
+	/* A __vpiScope starts with a __vpiHandle structure so this is
+	   a safe cast. We need the (void*) to avoid a dereferenced
+	   type punned pointer warning from some gcc compilers. */
+      compile_vpi_lookup((vpiHandle*)(void*)(&func_scope_), scope_label);
 }
 
 ufunc_core::~ufunc_core()

vvp/vpi_scope.cc

@@ -484,7 +484,10 @@ compile_scope_decl(char*label, char*type, char*name, char*tname,
 
 void compile_scope_recall(char*symbol)
 {
-      compile_vpi_lookup((vpiHandle*)&current_scope, symbol);
+	/* A __vpiScope starts with a __vpiHandle structure so this is
+	   a safe cast. We need the (void*) to avoid a dereferenced
+	   type punned pointer warning from some gcc compilers. */
+      compile_vpi_lookup((vpiHandle*)(void*)&current_scope, symbol);
       assert(current_scope);
 }