Import dhcpcd-10.0.3 with the following changes:

Import dhcpcd-10.0.3 with the following changes:

DHCP: Don't crash on a test run
dhcpcd: Fix off-by-one overflow when read() writes full BUFSIZ
privsep: fix strlcpy overflow in psp_ifname
privsep: Fix a FD leak when processes exit
dhcpcd: Use a local variable instead of the optind
dhcpcd: Guard against handling many SIGTERM/SIGINT
DHCP6: Send correct amount of used buffer for prefix exclude option
options: andsf6 is DHCPv6, not DHCP
options: introduce the uri option as opposed to a string
DHCP6: Set all requested addrs as not stale when starting discovery