dhcpcd-8.1.1 has been released with the following changes:
- IPv6: Fix a potential crash when udevs marks an interface ready.
- Linux: compat shim added for setproctitle(3).
- arc4random: fixed UB in compat shim.
- DHCP: Fix fallout from dhcpcd-8.1.0 for checksum calculation.
The last fix involved a lot a people, quite a few different fixes and played havoc with gcc-9.2 but should now be resolved.