libmicrodns and macOS

Testing on macOS, I get a segfault in libndi_discovery_start() because mdns_init() fails on macOS.

→ sudo lsof -i udp:5353
COMMAND     PID           USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
mDNSRespo   207 _mdnsresponder    6u  IPv4 0xd5130a19231fa5b3      0t0  UDP *:mdns
mDNSRespo   207 _mdnsresponder    7u  IPv6 0xd5130a19231fa89b      0t0  UDP *:mdns

It's probably best to use the DNSServiceBrowse() on macOS?