nrf_drv_clock_lfclk_request required by freeRTOS but is part of legacy drivers

[cp52]

SDK 15.2

port_cmsis_systick.c 

void vPortSetupTimerInterrupt( void )
{
    /* Request LF clock */
    nrf_drv_clock_lfclk_request(NULL);

    /* Configure SysTick to interrupt at the requested rate. */
    nrf_rtc_prescaler_set(portNRF_RTC_REG, portNRF_RTC_PRESCALER);
    nrf_rtc_int_enable   (portNRF_RTC_REG, RTC_INTENSET_TICK_Msk);
    nrf_rtc_task_trigger (portNRF_RTC_REG, NRF_RTC_TASK_CLEAR);
    nrf_rtc_task_trigger (portNRF_RTC_REG, NRF_RTC_TASK_START);
    nrf_rtc_event_enable(portNRF_RTC_REG, RTC_EVTEN_OVRFLW_Msk);

    NVIC_SetPriority(portNRF_RTC_IRQn, configKERNEL_INTERRUPT_PRIORITY);
    NVIC_EnableIRQ(portNRF_RTC_IRQn);
}

 nrf_drv_clock_lfclk_request is part of the legacy drivers that will eventually be removed? 

Does this mean for FreeRTOS I need to keep using the legacy clock driver?

Is this likely to change?

[cp52]

Also another problem with this:

nrf_drv_clock.c

#if NRF_MODULE_ENABLED(NRF_CLOCK)

Is this meant to be enabled via the sdk_config? 

How do I enable it?