diff --git a/mps/code/airtest.c b/mps/code/airtest.c
index 946e585bc2f..56e1bd8c129 100644
--- a/mps/code/airtest.c
+++ b/mps/code/airtest.c
@@ -90,14 +90,13 @@ static mps_gen_param_s obj_gen_params[] = {
   { 170, 0.45 }
 };
 
-static void test_main(int interior, int stack)
+static void test_main(void *marker, int interior, int stack)
 {
   mps_res_t res;
   mps_chain_t obj_chain;
   mps_fmt_t obj_fmt;
   mps_thr_t thread;
   mps_root_t reg_root = NULL;
-  void *marker = ▮
 
   res = mps_arena_create_k(&scheme_arena, mps_arena_class_vm(), mps_args_none);
   if (res != MPS_RES_OK) error("Couldn't create arena");
@@ -145,12 +144,14 @@ static void test_main(int interior, int stack)
 
 int main(int argc, char *argv[])
 {
+  void *marker = ▮
+
   testlib_init(argc, argv);
 
-  test_main(TRUE, TRUE);
-  test_main(TRUE, FALSE);
-  /* not test_main(FALSE, TRUE) -- see .fail.lii6ll. */
-  test_main(FALSE, FALSE);
+  test_main(marker, TRUE, TRUE);
+  test_main(marker, TRUE, FALSE);
+  /* not test_main(marker, FALSE, TRUE) -- see .fail.lii6ll. */
+  test_main(marker, FALSE, FALSE);
 
   printf("%s: Conclusion: Failed to find any defects.\n", argv[0]);
   return 0;