diff --git a/master.cfg b/master.cfg
index 10b9a4a..df20e2e 100644
--- a/master.cfg
+++ b/master.cfg
@@ -740,9 +740,7 @@ The parameters of the class are:
 
             ##################### Racy ######################
 
-            self.extra_make_check_flags.append ('RACY_ITER=5')
-
-            self.addStep (self.TestClass (self.make_command, self.extra_make_check_flags,
+            self.addStep (self.TestClass (self.make_command, self.extra_make_check_flags + [ 'RACY_ITER=5' ],
                                           self.test_env,
                                           doStepIf = scheduler_is_racy,
                                           hideStepIf = scheduler_is_not_racy))