While ngx_get_full_name() might have a bit more descriptive arguments,
the ngx_conf_full_name() is generally easier to use when parsing
configuration and limits exposure of cycle->prefix / cycle->conf_prefix
details.

The ngx_get_full_name() should be used instead.

The ngx_get_full_name() function takes more readable arguments list.

If a relative path is set by variables, then the ngx_conf_full_name()
function was called while processing requests, which causes allocations
from the cycle pool.

A new function that takes pool as an argument was introduced.

Some systems (notably NetBSD and OpenBSD) lack AI_ADDRCONFIG support.

Reported by Piotr Sikora.

This seems to be the case at least under Cygwin, where build was broken
by 05ba5bce31e0 (1.5.3).

Reported by Kevin Worthington,
http://mailman.nginx.org/pipermail/nginx/2013-August/040028.html.

This is done by passing AI_ADDRCONFIG to getaddrinfo().

On Linux, setting net.ipv6.conf.all.disable_ipv6 to 1 will now be
respected.

On FreeBSD, AI_ADDRCONFIG filtering is currently implemented by
attempting to create a datagram socket for the corresponding family,
which succeeds even if the system doesn't in fact have any addresses
of that family configured.  That is, if the system with IPv6 support
in the kernel doesn't have IPv6 addresses configured, AI_ADDRCONFIG
will filter out IPv6 only inside a jail without IPv6 addresses or
with IPv6 disabled.