Fix 32-bit build error: include util.h to get int64 typedef

src/bitcoinrpc.h

@@ -16,6 +16,8 @@ class CBlockIndex;
 #include "json/json_spirit_writer_template.h"
 #include "json/json_spirit_utils.h"
 
+#include "util.h"
+
 json_spirit::Object JSONRPCError(int code, const std::string& message);
 
 void ThreadRPCServer(void* parg);