Attempt fix 2

Author: mcbarton

src/xinterpreter.cpp

@@ -132,7 +132,8 @@ __get_cxx_version ()
         const std::string& code,
         bool silent,
         bool /*store_history*/,
-        nl::json /*user_expressions*/
+        nl::json /*user_expressions*/,
+        bool allow_stdin
     )
     {
         nl::json kernel_res;