`DnsServiceConstructInstance` and `DnsServiceFreeInstance` are missing from dnsapi. Applications that import them abort at startup on the unimplemented function. The Elgato Stream Deck software hits this: it calls `DnsServiceConstructInstance` to build an mDNS service instance (for example \_vstreamdeck2.\_tcp.local) before advertising it. `DnsServiceConstructInstance` builds a DNS_SERVICE_INSTANCE from its arguments and `DnsServiceFreeInstance` releases it. Neither touches the network, so they are implemented directly. The change also adds the DNS_SERVICE_INSTANCE structure and the two prototypes to windns.h. `DnsServiceRegister`, which the same applications call next to publish the instance, is still missing and will abort. That needs real mDNS support. Signed-off-by: Thomas Portal portal.thomas@protonmail.com -- v2: dnsapi/tests: Add tests for DnsServiceConstructInstance(). dnsapi: Implement DnsServiceConstructInstance() and DnsServiceFreeInstance(). https://gitlab.winehq.org/wine/wine/-/merge_requests/11200