unrealircd6: update to 6.0.3

UnrealIRCd 6.0.3
=================

A number of serious issues were discovered in UnrealIRCd 6. Among these is
an issue which will likely crash the IRCd sooner or later if you /REHASH
with any active clients connected.
We suggest everyone who is running UnrealIRCd 6 to upgrade to 6.0.3.

If you are already running UnrealIRCd 6 then read below. Otherwise, jump
straight to the [summary about UnrealIRCd 6](#Summary) to learn more
about UnrealIRCd 6.

Fixes:
* Crash in `WATCH` if the IRCd has been rehashed at least once. After doing
  a `REHASH` with active clients it will likely corrupt memory. It may take
  several days until after the rehash for the crash to occur, or even
  weeks/months on smaller networks (accidental triggering, that is).
* A `REHASH` with certain remote includes setups could cause a crash or
  other weird and confusing problems such as complaining about unable
  to open an ipv6-database or missing snomask configuration.
  This only affected some people with remote includes, not all.
* Potential out-of-bounds write in sending code. In practice it seems
  harmless on most servers but this cannot be 100% guaranteed.
* Unlikely triggered log message would log uninitialized stack data to the
  log file or send it to ircops.
* Channel ops could not remove halfops from a user (`-h`).
* After using the `RESTART` command (not recommended) the new IRCd was
  often no longer writing to log files.
* Fix compile problem if you choose to use cURL remote includes but don't
  have cURL on the system and ask UnrealIRCd to compile cURL.

Enhancements:
* The default text log format on disk changed. It now includes the server
  name where the event was generated. Without this, it was sometimes
  difficult to trace problems, since previously it sometimes looked like
  there was a problem on your server when it was actually another server
  on the network.
  * Old log format: `[DATE TIME] subsystem.EVENT_ID loglevel: ........`
  * New log format: `[DATE TIME] servername subsystem.EVENT_ID loglevel: ........`

Changes:
* Any MOTD lines added by services via
  [`SVSMOTD`](https://www.unrealircd.org/docs/MOTD_and_Rules#SVSMOTD)
  are now shown at the end of the MOTD-on-connect (unless using a shortmotd).
  Previously the lines were only shown if you manually ran the `MOTD` command.

Developers and protocol:
* `LIST C<xx` now means: filter on channels that are created less
  than `xx` minutes ago. This is the opposite of what we had earlier.
  `LIST T<xx` is now supported as well (topic changed in last xx minutes),
  it was already advertised in ELIST but support was not enabled previously.


(nia)