system_task.cpp is very much meant to be an internal part of the system - it’s already included in the system module. Including it in your application will only lead to bad things!
I’d like to know what your goals are so I can help you find an alternative route.
Very simply I am just trying to get my code to compile (all of it). The driving factor in trying to include system_task.cpp into my code was that I was getting the error undefined reference “Spark_Idle_Events”. I was not trying to call anything directly in system_task.cpp just make it available to solve the “Spark_Idle_Events” problem.
For that matter I am not calling “Spark_Idle_Events” directly either not sure what old code is needing it.
Spark_Idle_Events() is an internal function that indirectly called from Spark.process(). I’ve tried with both modular and monolithic firmware and both link fine here.
Could you share your code and/or details about how you are building it so we can troubleshoot?
EDIT: I’ve reproduced the problem. Calls to the deprecated SPARK_WLAN_Loop() will cause this error. Please change those calls to Spark.process() and the problem will disappear!