I found this article by Jungle Dave titled Leopard DNS Issues (and work-around), which explains how libcurl built with IPv6 support may cause trouble on MacOS X 10.5 (Leopard).
According to him, that’s because getaddrinfo() causes a SRV lookup to be made and that may be either slow or get discarded completely and thus cause trouble.
This just adds another problem to getaddrinfo() resolves then, since we already have the problem with it when resolving round-robin DNSes since more or less every machine has a bad /etc/gai.conf setup that makes getaddrinfo() return a sorted list instead of the “random” one DNS admins in the wild would prefer the users to use…
I know this is a dear subject for many people but I feel I just have to spell it out after having read this engadget notice about