A range is specified with a dash.  For each port in a range a separate listen
socket is created.

Examples:

    listen 8080-9000;
    listen example.com:80-88;

Previously the ngx_inet_resolve_host() function sorted addresses in a way that
IPv4 addresses came before IPv6 addresses.  This was implemented in eaf95350d75c
(1.3.10) along with the introduction of getaddrinfo() which could resolve host
names to IPv6 addresses.  Since the "listen" directive only used the first
address, sorting allowed to preserve "listen" compatibility with the previous
behavior and with the behavior of nginx built without IPv6 support.  Now
"listen" uses all resolved addresses which makes sorting pointless.

Previously only one address was used by the listen directive handler even if
host name resolved to multiple addresses.  Now a separate listening socket is
created for each address.

Previous interface of ngx_open_dir() assumed that passed directory name
has a room for NGX_DIR_MASK at the end (NGX_DIR_MASK_LEN bytes).  While all
direct users of ngx_dir_open() followed this interface, this also implied
similar requirements for indirect uses - in particular, via ngx_walk_tree().

Currently none of ngx_walk_tree() uses provides appropriate space, and
fixing this does not look like a right way to go.  Instead, ngx_dir_open()
interface was changed to not require any additional space and use
appropriate allocations instead.

Previously, if an SRV record was successfully resolved, but all of its A
records failed to resolve, NXDOMAIN was returned to the caller, which is
considered a successful resolve rather than an error.  This could result in
losing the result of a previous successful resolve by the caller.

Now NXDOMAIN is only returned if at least one A resolve completed with this
code.  Otherwise the error state of the first A resolve is returned.