Import dhcpcd 4.0.0-beta5.

dhcpcd is a small DHCP client, supporting most, if not all, features of
dhclient.  It is much smaller (1/6 of the size on amd64), but still
supports many of the more advanced modern RFCs like IPv4LL (RFC 3927), 
Classless Static Routes (RFC 3442) and Node-specific Client Identifiers
(RFC 4361).  It was written by Roy Marpled, partly in reply to the
discussion of the DHCP client Sommer of Code project.
Pull in 4c8ba2435551fdffc65c1830befe2d5abe04221a:
Fix a signal race when daemonising.
Merge ebdbc57c7f54b27fd8d472cb357c0b533b9a0c2e:
Fix compilation.
Merge e28f0a8f857fad837ac78a93921873361d60747c and
c46587eb3d02a4750d0aaf6e7a0a19f24b3d7fa8:
Correctly handle ARP replies and fix a pointer misuse.
Import dhpcd-4.0.0rc3. Major changes since beta4:
- support for link state notification (e.g. renew lease after carrier
  returned)
- support to start go into background immediately
- don't cleanup interface state. dhcpcd will leave the interface in the
  same state as before if the lease uses separate addresses. -p still
  stops it from removing the configured address on exit
- various smaller bugfixes, optimisations and cleanups
Import dhcpcd-4.0.1:
- basic resolvconf like functionality to combine the resolv.conf entries
from running instances
- improve timer handling to not break with early wake ups and other edge
cases related to the kernel time granularity
- improve handling of dhcpcd -n and rebinding after carrier loss to
better deal with changing networks
- add option to black list servers based on server id
- don't check for ARP conflict if the interface already has the address
- improve signal handling during vfork/exec
Import dhcpcd-4.0.7 with the following changes from dhcpcd-4.0.1

DHCP_DECLINE now includes the IP and Server in the message.
Trailing NULLs are stripped from string options.
ntpd is only restarted if it is already running.
ClientID is no longer sent by default.
CSR comes before routers and static routes as per RFC 3442.
Host routes are now added correctly.
If a the interface link flaps but status does not change, do not reset the timer.
Import dhcpcd-4.0.8

Changes since dhcpcd-4.0.7:
 * broadcast address correctly set for hooks
 * respect renewal time if given but rebind time is not
 * nohook 20-resolv.conf works as well as nohook resolv.conf
 * short hostnames are now sent
Import dhcpcd-4.0.9

Changes from dhcpcd-4.0.8
 * Add a bit more pedantic error checking
 * Zero the DHCP message struct instead of trying to terminate the options
Import dhcpcd-4.0.10

Changes since dhcpcd-4.0.9
 * Move the ARP check to after the REQUEST to be more RFC2131 conformant.
Import dhcpcd-4.0.11

Fixes since dhcpcd-4.0.10 include recovery from send_packet failure
Import dhcpcd-4.0.12

Fixes since dhcpcd-4.0.11 include:
 * Logging to LOG_DAEMON instead of LOG_LOCAL0
 * Checking for POLLERR and POLLNVAL
 * Only opening raw sockets when we have a working link
Import dhcpcd-4.0.13

Fixed since dhcpcd-4.0.12 include
 * Every DHCP message now requires a ServerID as some rogue DHCP servers
   NAK without one.
 * Extra UDP validation is now done for testing dhcpcd over a loopback
Import dhcpcd-5.0.0

Major changes from dhcpcd-4 include
 * Single daemon can now run DHCP on multiple interfaces at the same time
 * Configuration profiles per interface, ssid, arping and fallback
 * Listens to 3rd party programs changing routing information
 * Supports DHCP INFORM over PPP
 * Can configure static options for destination address
 * Control socket so 3rd party program can control or listen directly
   to dhcpcd events
 * Is also a BOOTP client
Import dhcpcd-5.0.1

Changes from dhcpcd-5.0.0
 * Silence compile warnings on Sparc64
 * Fix existing address detection
Update dhcpcd to 5.0.2

Changes from 5.0.1 include
 * -n option now starts dhcpcd if not already started
 * 29-lookup-hostname hook installed by default, but skipped in dhcpcd.conf
 * Fix warning about missing dirs if we don't have any existing state
 * Fix compile on some Linux distros re linux/wireless.h
Re import right version
Import dhcpcd-5.0.3

Changes from 5.0.2
 * Fix crash when ifa_addr from getifaddrs(3) is NULL
Import dhcpcd-5.0.4

Changes from dhcpcd-5.0.3 include
 * ServerID requirement in DHCP messages can be toggled in dhcpcd.conf
 * If MTU is requested, don't apply if less than 576
 * Enforce a minimum lease time of 20 seconds
Import dhcpcd-5.0.5

Changes since 5.0.4
 * Fixed dstaddr detection for PtP links at startup
 * Default to requesting MTU in dhcpcd.conf