replacing an existing IPv4 address with the same values.
As such, we need to maintain a list of configured IPv4 addresses
for each interface so we know when to add it and when to skip it
to avoid receiving bogus RTM_DELADDR messages from ourself.
and dhcp.c
Split configure.c into script.c and move the rest into dhcp.c
This starts the goal of making the base of dhcpcd protocol agnostic and
working towards building IPv4 and/or IPv6 code only to reduce size and
allow growing any future new protocol easier.
