Energy optimized port of FreeRTOS 6 for EFM32

I had download the file freertos6.zip
When I ‘make’ the project then I get the following error:
Error: no definition for “SYSTEM_ChipRevisionGet” [referenced from D:FreeRTOS_6FreeRTOSiarFreeRTOS-EFM32-G890DebugObj
What is wrong?

Energy optimized port of FreeRTOS 6 for EFM32

Please see my reply to this thread:
https://sourceforge.net/projects/freertos/forums/forum/382005/topic/4790081 Regards.