According to
https://developer.apple.com/documentation/dnssd/1804733-dnsserviceregister
the DNSServiceRef is initialized only if DNSServiceRegister() returns
kDNSServiceErr_NoError.  The faulty error handling code could
therefore crash.

See commit dfc67c45

Snapcast's protocol documentation is wrong, see
https://github.com/badaix/snapcast/pull/811

Regression by commit a22d1c88

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1097

At least I believe libmpdclient is reading env. var. as second:
https://github.com/MusicPlayerDaemon/libmpdclient/blob/master/src/settings.c#L142

ncmpc manual also mentions MPD_TIMEOUT being is second.