adding pcu_order field to pcu_msg
adding pcu_order field to pcu_msg

this is a consequence of pcu_msg
pulling double-duty as the
thread-specific data container,
added a comment to that effect

yangf4/core,yangf4/core,yangf4/core,YetAnotherMinion/core,YetAnotherMinion/core,YetAnotherMinion/core,yangf4/core,yangf4/core,YetAnotherMinion/core,YetAnotherMinion/core