Fix examples description, and use less ambiguous wording.
Assume POSIX: write() takes size_t and returns ssize_t
fleanse out oldrdist support
Return RSN (WPA) information to userland during wireless scan, and
make ifconfig show whether a wireless network uses WEP or WPA.
Since struct ieee80211_nodereq grows in size old ifconfig won't be
able to scan when running on a new kernel.
While here, add missing ioctl constant IEEE80211_WPA_CIPHER_BIP.
ok jsg@
struct ucred; for fstat _KERNEL block
repair prototypes
Improve the scheduler, better and simpler.

- Get rid of the scheduler_batch structure. The scheduler can now return
  envelopes of different types in a single run, interlacing them to avoid
  batch effects.

- Ask for an acknowledgement from the queue when removing or expiring
  an envelope to benefit from the inflight envelope limitation mechanism.
  This ensures that the scheduler always keeps sending envelopes at a rate
  that the queue can sustain in all cases.

- Limit the number of envelopes in a holdq.  When a holdq is full,
  new envelopes are put back in the pending queue instead, with a
  shorter retry time.

- Plumbing for proc-ified schedulers.

imsg version bump. smtpctl stop before updating.

ok gilles@
make the control process broadcast verbose/profile admin requests directly,
rather than going through the parent process. simplify code in the meantime.