Or you make the case that the OS should ship a DNS server. It can handle DNS forwarding and iterative queries anyway (iterative queries as you often need them for dnssec) and the logic for serving DNS responses is ok'ish (DNS name dedup and length restrictions being the biggest complexity issue).

I am not super happy with systemd-resolved but it solves this particular issues. No requirement to use libc, but same (os configurable) behavior for all users.