Import dhcpcd-6.3.0 with the following changes:

 * IAID must be inside an interface block.
 * Detect IPv6 address flags on Linux.
 * Check that we have ctrl_interface defined in wpa_supplicant.conf and pass this parameter to wpa_cli(8). If not set, warn about not interacting with wpa_supplicant(8).
 * Skip Virtual Interface Masters. Currently this only applies to FreeBSD VAP masters as dhcpcd should only work on wlandev created clones.
 * Fix handling of ARP failures, thanks to Sebastian Huber.
 * Implement RFC 1321 MD5 Message-Digest if not provided in libc.
 * Implement RFC 2104 HMAC Keyed Hashing.
 * Implement RFC 3118 Authentication for DHCP Messages and RFC 3315 Authentication options.
 * Add nodhcp and nodhcp6 directives. Thanks to Sebastian Huber for the initial patch and testing.
 * Implement support for RFC 3203, FORCERENEW message.
 * Implement Force Renew Nonce Capability option, RFC6704
 * Support RECONFIGURE DHCPv6 messages.
 * Add support for DHCP auto configuration, RFC 2563.
 * Add support for the following RFCs
   + DHCP SLP Directory Agent, RFC2610
   + DHCP Name Service Search, RFC2937
   + DHCP PANA Authentication Agent, RFC5192
   + DHCP Lost Server, RFC5223
   + DHCP CAPWAP, RFC5417
   + DHCP Mobility Services, RFC5678
   + DHCP SIP UA, RFC6011
   + DHCP ANDSF, RFC6153
   + DHCP RDNSS Selection for MIF Nodes, RFC6731
   + DHCP TFTP Server Address, RFC5859
   + DHCP PXELINUX, RFC5071
   + DHCP Access Network Domain Name, RFC5986
   + DHCP Virtual Subnet Selection, RFC6607
   + DHCP Relay Agent Remote-ID, RFC4649
   + DHCP Relay Agent Subscriber-ID, RFC4580
   + DHCPv6 Relay-ID, RFC5460
   + DHCPv6 LIS Discovery, RFC5986
   + DHCPv6 SIP UA, RFC6011
   + DHCPv6 Network Boot, RFC5970
   + DHCPv6 Home Info Discovery in MIPv6, RFC6610
   + DHCPv6 RDNSS Selection for MIF Nodes, RFC6731
   + DHCPv6 Kerberos, RFC6784
   + DHCPv6 Relay-Triggered Reconfiguration, RFC6977
   + DHCPv6 SOL_MAX_RT, RFC7083
 * Open UDP sockets for *.*.*.*:bootpc and $ip_address:bootpc to avoid kernel ICMP unreachable messages
 * Moved global variables into context variables so dhcpcd is entirely thread safe.
   dhcpcd doens't use threads, but it can now be used in a pure threads (ie no process) environment.
 * Remove DEBUG_MEMORY guard and always free memory and resources. Remove all atexit(3) and exit(3) calls, instead exiting via the eloop.
 * Replace get_line with sscanf where applicable.
 * Remove custom set_cloexec and set_nonblock functions. Instead pass O_CLOEXEC or SOCK_CLOEXEC to open, socket, etc.
 * Don't use PATH_MAX - we already know the maximum length from the initial directory and IF_NAMESIZE.
 * Add a USE_SIGNALS define. If we're not using signals then we also create a control socket in the non MASTER case. We then use this to communicate instead of signals.
 * Fix arping moving to the next test if we find the IP address but do not have a profile for it. Thanks to David McGurty for the analysis.
 * Respect initial commandline arguments when rebooting via a signal.
Import dhcpcd-6.3.1 with the following changes

  * all issuses reported by clang static analyser have been resolved.