add BT_SetTerminate to all threads

src/main.cpp

@@ -780,6 +780,7 @@ LRESULT CALLBACK splash_proc(HWND hWndDlg, UINT Msg, WPARAM wParam, LPARAM lPara
 HWND splash_dialog;
 void splash_thread_loop()
 {
+    BT_SetTerminate();
     splash_dialog = CreateDialog(hInst, MAKEINTRESOURCE(IDD_SPLASH), NULL, reinterpret_cast<DLGPROC>(splash_proc));
 
     MSG msg;