Replace Windows specific thread handling

Use the platform independent primitives instead.
diff --git a/win/winvnc/QueryConnectDialog.h b/win/winvnc/QueryConnectDialog.h
index b28de19..de5e31e 100644
--- a/win/winvnc/QueryConnectDialog.h
+++ b/win/winvnc/QueryConnectDialog.h
@@ -21,24 +21,26 @@
 #ifndef __WINVNC_QUERY_CONNECT_DIALOG_H__
 #define __WINVNC_QUERY_CONNECT_DIALOG_H__
 
-#include <rfb/Threading.h>
 #include <rfb_win32/Dialog.h>
 #include <rfb/util.h>
 
+namespace os { class Thread; }
+
 namespace network { class Socket; }
 
 namespace winvnc {
 
   class VNCServerWin32;
 
-  class QueryConnectDialog : public rfb::Thread, rfb::win32::Dialog {
+  class QueryConnectDialog : public os::Thread, rfb::win32::Dialog {
   public:
     QueryConnectDialog(network::Socket* sock, const char* userName, VNCServerWin32* s);
     virtual void startDialog();
-    virtual void run();
     network::Socket* getSock() {return sock;}
     bool isAccepted() const {return approve;}
   protected:
+    // Thread methods
+    virtual void worker();
 
     // Dialog methods (protected)
     virtual void initDialog();