Probably Invalid MainThreadID

[innerand]

Called at this point, this returns the ID of hSigSetupThread which is different from the MainThreadID.

https://github.com/michaelbecker/freertos-addons/blob/8f408a2f37e0322439d9a058b0f8c96bb0db65ab/Linux/portable/GCC/Linux/port.c#L417

Breaks vTaskSchedulerEnd() as the actual main thread is never woken.