Log Message:
Import dhcpcd-6.4.7 with the following changes:
  *  make test works again
  *  Many bounds checking fixes from Tobias Stoeckmann
  *  Improve error when the authentication token cannot be found
  *  close the IPv4 specific UDP socket when done sending
  *  Implemented a write queue to the control sockets
  *  Only send interfaces to control sockets when in a BOUND state
  *  Add a sample controlgroup directive to dhcpcd.conf to make setup easier
  *  Add variables if_oneup and if_ipwaited so hook scripts know the overall
     state of dhcpcd better
  *  Pass RC_SVCNAME from enviromment to hooks so that a service hook can
     know it's name (may not be dhcpcd)
  *  Document every variable set for dhcpcd-run-hooks(8)
  *  Use the nl80211 interface on Linux to get the wireless SSID if we fail
     to get it via WEXT
  *  Allow SSIDs with non printable characters to be used in ssid selection
     in dhcpcd.conf
  *  Add an unprivileged control socket so that normal users can obtain
     dhcpcd running state
  *  Remove all instances of if_indextoname as we already know the index
  *  Only bring in linux/ipv6.h for linux AND glibc
  *  Add _DEFAULT_SOURCE #define to to make glibc-2.20 happy
  *  Check we have allocated IPv6 resources before checkings RA's
  *  configure errors are now logged to config.log
  *  Only hunt for a cross compiler if build != host
  *  Detect removal of IPv6 routes
  *  Don't add link-local addresses to POINTOPOINT interfaces
  *  Don't discard expired DHCPv6 leases when dumping them
  *  If a DHCPv6 lease has no timers, expire it right away
  *  Report delegated addresses
  *  Call dhcpcd-run-hooks correctly when delegated prefixes already exist
  *  Fix a memory error when ia_* config exists but IPv6 is disabled
  *  Ensure servername and bootfile are safely exported
  *  Sanitise the following characters using svis(3) with VIS_CTYLE and
     VIS_OCTAL:
         | ^ & ; < > ( ) $ ` \ " ' <tab> <newline>
     This allows a non buggy unvis(1) to decode it 100% and stays compatible
     with how dhcpcd used to handle encoding on most platforms.
     For systems that supply svis(3) there is a code reduction, for systems
     that do not, a slight code increase. This change mitigates systems
     affected by bash CVE-2014-6271 and CVE-2014-7169.

OK: jperkin@