NetBSD 9.3 and Amiga loadbsd

[Roc Vallès <vallesroc%gmail.com@localhost>]

A while ago (October 2021), I had installed a previous 9.x build and
found that, unlike source code and documentation, the loadbsd in
tools/ directory does not support the flag for using the serial port
as console. Dug a little deeper by asking around (on IRC), and I found
the reason is that nobody had built it for years (to the point of
syntax errors sleeping undetected for years in the main C source
file), as it is an AmigaOS tool, requires AmigaOS headers, and cannot
be built by netbsd's build system.

I did manage to coerce it to build and make it so others can build it,
too: https://github.com/rvalles/netbsd_amiga_loadbsd_pleasebuild

Unfortunately, it seems I didn't push this enough (I likely only
mentioned it on IRC), and Netbsd 9.3 still ships the ancient version.
It would be nice if a maintainer could try and resolve this, which
could be done by building their own binary or shipping mine (uploaded
as a "release" in github above).

-- Roc