The relationship with GNU & SUN would be that the SUN & VAX were the first target platforms for GCC/GAS/Binutils. So it would have been expected that if you were running a 68000 version of GCC it’d probably be running on a SUN-2 or SUN-3. Not to mention it was their build platform as mentioned here:

ftp://ftp.cs.purdue.edu/pub/comer/XINU-68K.README

There is some additional platforms here:

I haven’t tried to run any of it yet though.

From: arnold@skeeve.com
Sent: Thursday, 28 December 2017 10:07 PM
To: tuhs@tuhs.org; jsteve@superglobalmegacorp.com
Subject: Re: [TUHS] XINU for the 68000 / 68010

Jason Stevens <jsteve@superglobalmegacorp.com> wrote:

> I came across this page while looking for man pages to SYSVr3 for

> someone... Completely unrelated but I thought it’d be interesting

> to someone. Apparently it can be built with GCC/GAS/Binutils from a

> 680x0 based SUN.

Small clarification: The AT&T 3B1 isn't related to Suns. It was

made for AT&T by Convergent. It was a nice box; I owned one for a while

and have many happy memories thereof.

> http://unixpc.taronga.com/xinu7300/

Hmmm, are there other Xinu versions in the archive?

Thanks,

Arnold