From what I can see the BSP_INCLUDE_RTC_DRIVER == TRUE effectively links the RTC to the C time functions.
With the ConnectEM there is not a hardware RTC on board and the rtc.c file that will get included in the BSP does not have the definitions for any functions.
I believe that you first need to get your hardware RTC and then write all of the access functions for it, so that they match the NaRtcxxxxFunc_t function prototypes.
Once you have all of the functions defined then you need to set them up in naRtcDeviceTable in rtc.c and then you can set the flag equal to true, and the 'C' time functions should work.
If you do not have a hardware RTC you can use naTimeFunctionInstall() to set up a software timer to get the 'C' time functions working.