added js_std_await() and use it to wait for the evaluation of a module (github issue #219)

qjs.c

@@ -64,6 +64,7 @@ static int eval_buf(JSContext *ctx, const void *buf, int buf_len,
             js_module_set_import_meta(ctx, val, TRUE, TRUE);
             val = JS_EvalFunction(ctx, val);
         }
+        val = js_std_await(ctx, val);
     } else {
         val = JS_Eval(ctx, buf, buf_len, filename, eval_flags);
     }