For IN args. If set it...

• removes the __mig_deallocate for OOL IN data, which is usually done after the implementation has been called;

• adds a boolean_t NAMESCopy for the IN arg NAME to indicate whether the data will persist nevertheless (OOL case) or has to be copied by the implementation (inline case).

Cf., ?exec server, exec.defs.

I.e., the IN args' memory region (OOL case) persists after the implementation has returned.