Try to silence unused function warning in travis

test/unit/core/test_timers.c

@@ -177,5 +177,9 @@ timers_suite(void)
     /* TESTFUNC(test_bug52748), */
     TESTFUNC(test_timers)
   };
+  testfunc tests_unused[] = {
+    TESTFUNC(test_bug52748)
+  };
+  LWIP_UNUSED_ARG(tests_unused);
   return create_suite("TIMERS", tests, LWIP_ARRAYSIZE(tests), timers_setup, timers_teardown);
 }