It turns out c-ares returns an error when asked to resolve a host name with
ares_getaddrinfo using port number 0.
Reported as a c-ares bug here: https://github.com/c-ares/c-ares/issues/517
The work-around is to simply use port 80 instead, as the number typically does
not make a difference and a non-zero number works for c-ares.
Fixes#10759
Reported-by: Matt Jolly
Closes#10789
