Replace Windows specific thread handling

Use the platform independent primitives instead.
diff --git a/win/winvnc/QueryConnectDialog.cxx b/win/winvnc/QueryConnectDialog.cxx
index 8e50696..103621e 100644
--- a/win/winvnc/QueryConnectDialog.cxx
+++ b/win/winvnc/QueryConnectDialog.cxx
@@ -41,7 +41,7 @@
 QueryConnectDialog::QueryConnectDialog(network::Socket* sock_,
                                        const char* userName_,
                                        VNCServerWin32* s)
-: Thread("QueryConnectDialog"), Dialog(GetModuleHandle(0)),
+: Dialog(GetModuleHandle(0)),
   sock(sock_), approve(false), server(s) {
   peerIp.buf = sock->getPeerAddress();
   userName.buf = strDup(userName_);
@@ -54,7 +54,7 @@
 
 // - Thread overrides
 
-void QueryConnectDialog::run() {
+void QueryConnectDialog::worker() {
   countdown = timeout;
   try {
     if (desktopChangeRequired() && !changeDesktop())