timer_test.c fails to compile with clang-11

timer_test.c:194:6: error: cast to smaller integer type 'isc_timertype_t' from 'void *' [-Werror,-Wvoid-pointer-to-enum-cast]
        if ((isc_timertype_t)event->ev_arg == isc_timertype_ticker) {
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
Makefile:250: recipe for target 'timer_test.lo' failed