fix cast warning caught on windows

ixwebsocket/IXSocket.cpp

@@ -129,7 +129,7 @@ namespace ix
     }
 
     // Wake up from poll/select by writing to the pipe which is watched by select
-    bool Socket::wakeUpFromPoll(uint8_t wakeUpCode)
+    bool Socket::wakeUpFromPoll(uint64_t wakeUpCode)
     {
         return _selectInterrupt->notify(wakeUpCode);
     }

ixwebsocket/IXSocket.h

@@ -57,7 +57,7 @@ namespace ix
 
         // Functions to check whether there is activity on the socket
         PollResultType poll(int timeoutMs = kDefaultPollTimeout);
-        bool wakeUpFromPoll(uint8_t wakeUpCode);
+        bool wakeUpFromPoll(uint64_t wakeUpCode);
 
         PollResultType isReadyToWrite(int timeoutMs);
         PollResultType isReadyToRead(int timeoutMs);