I confirm RFC 2553 specifically exclude loopback interface for AI_ADDRCONFIG.
Attached is a trivial patch.
--- man3/getaddrinfo.3.orig 2012-02-21 09:38:54.000000000 +0100 +++ man3/getaddrinfo.3 2012-02-21 09:39:42.000000000 +0100 @@ -378,6 +378,8 @@ only if the local system has at least one IPv4 address configured, and IPv6 addresses are only returned if the local system has at least one IPv6 address configured. +The loopback address is not considered for this case as valid +as a configured address. .PP If .I hint.ai_flags
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