Using freeRTOS with lwip

[SoFa]

I am currently trying to setup lwIP with freeRTOS using CubeMX. Using the generated code, creates a defaultTask, which initilializes the lwIP stack. It works just fine to ping the controller, but what i don't understand is, that in lwipopts.h NO_SYS is set to 1and thus the whole initialization is made for a configuration without RTOS, but it still works.

When i include the sys_arch, also provided by ST(uses the cmsis_os) i get a linker error, which can't find tcpip_try_callback, which is declared in tcpip.h but never defined. Do i have to do that manually or what am i missing here?

Thanks a lot for your help