*) Corrected the directive name in the ngx_mail_auth_http_module
   error message.

*) Don't let the well-known port in the "listen" directive to
   override the already set "protocol".

*) Fixed sorting of listen addresses (ticket #187).  For http module
   this problem was already fixed in r4756.

*) Removed a stale "AF_INET only" comment.  IPv6 client connections
   in mail modules have been supported since r2856.

*) Fixed handling of AF_UNIX addresses in "listen".  This makes AF_UNIX
   addresses in mail officially supported.

*) Whitespace fix.

Fixed compilation with -Wmissing-prototypes.  Added a commented
out -Wmissing-prototypes to CFLAGS.  It is commented out to not break
builds with 3rd party modules.

Nuke NGX_PARSE_LARGE_TIME, it's not used since 0.6.30.  The only error
ngx_parse_time() can currently return is NGX_ERROR, check it explicitly
and make sure to cast it to appropriate type (either time_t or ngx_msec_t)
to avoid signedness warnings on platforms with unsigned time_t (notably QNX).

Support for TLSv1.1 and TLSv1.2 protocols was introduced in OpenSSL 1.0.1
(-beta1 was recently released).  This change makes it possible to disable
these protocols and/or enable them without other protocols.

The "so_keepalive" directive in mail module was deprecated.

Thanks to Vsevolod Stakhov for initial work.