auto::funcptr: In r24193, I refactored code out of runstep() into _cast_void_pointers_msg() and _set_positive_result(). I renamed one test file, gave it new content and added two more test files.
The remaining uncovered code deals with the case where there are problems identifying the user's JIT-capability. This situation will be difficult too mock, so I'm going to be satisfied with the current coverage level and close the ticket.
