Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFH r226345, r226464, r226879:
Make dhclient use a pid file. Modify the rc script accordingly, fix some bugs

Approved by: des (mentor)

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

- Remove references to unexisting man pages

PR: docs/116099
Submitted by: Ben Kaduk <minimarmot@gmail.com>
Approved by: re (bmah)
MFC after: 3 days

Revert the addition of -p. It's flawed in that dhclient should not run
on an interface without carrier. devd should be used instead to handle
link up/down events.

Put on the right path by: brooks, sam

Bump the document date. s/dhclient/.Nm/

Suggested by: ru

Add a -p switch to dhclient. The switch tells dhclient to persist
despite the interface link status.

Add dhclient_flags_iface and background_dhclient_iface rc.conf options.
(where iface is a specific interface). These can be used to give
interface specific flags to dhclient.

Reviewed by: brooks@

Mention the -b flag in the SYNOPSIS.

MFC after: 1 week

Bump document date.

Reminded by: ru

Document -b flag of dhclient.

Reviewed by: ru
MFC after: 3 days

Line up the markup.

Approved by: re (blanket)

This commit was generated by cvs2svn to compensate for changes in r147072,
which included commits to RCS files with non-trunk default branches.

Import the OpenBSD dhclient as shipped with OpenBSD-3.7 (the tag
OPENBSD_3_7).