Previously, ngx_utf8_decode() was called from ngx_utf8_length() with
incorrect length, potentially resulting in out-of-bounds read when
handling invalid UTF-8 strings.

In practice out-of-bounds reads are not possible though, as autoindex, the
only user of ngx_utf8_length(), provides null-terminated strings, and
ngx_utf8_decode() anyway returns an errors when it sees a null in the
middle of an UTF-8 sequence.

Reported by Yunbin Liu.

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.