prop_{array,dictionary}_copyout_ioctl().
- Implement prop_{array,dictionary}_recv_syscall(), which
takes as parameter the pref we got from kernel and internalize it,
and unmaps the buffer prop_{array,dictionary}_copyout() mapped for us.
- add a prop_{array,dictionary}_send_syscall() for symetry, which is
an alias to prop_{array,dictionary}_externalize_to_pref()
Discussed on tech-kern@ and tech-userlevel@