Log Message:
Import dhcpcd-6.6.3 with the following changes:

  *  Log which IP address we are ARPing.
  *  Only free other ARP states if not assinging an IPv4LL address.
  *  Reload global config when running per interface commands.
     This matches the signal behaviour.
  *  If we don't have a hardware address, fallback to creating a default
     IAID from the interface name and index as we used to.
  *  Loopback interfaces have routes scoped to the host only.
  *  If we don't have a hwlen and no clientid has been set, force a DUID
     based ClientID.
  *  Disable IPv6RS if a loopback, pointopoint or not a multicast interface.
  *  If allowinterfaces is not specified, allow all configured interfaces
     to work, such as loopback and ppp.
  *  When not daemonising, don't exit on timeout.
  *  Zero length UDP packets are not an error condition on the socket.
     Thanks to Micha? K?pie?.
  *  If the IP address is still on the interface when reading a lease,
     fake add the address and routes so the lease can be cleaned up if needed.