Comment # 14 on bug 1131075 from Matwey Kornilov

(In reply to Ludwig Nussel from comment #11)
> try
> 
> # echo "d /run/netconfig 0755 root root -" > /etc/tmpfiles.d/netconfig.conf

This makes dnsmasq successfully running both with

resolv-file=/run/netconfig/resolv.conf

and

resolv-file=/etc/resolv.conf