Cross-building [was Re: CMD MSCP SCSI problems? (again?)]

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

>>> Wow, I've not compiled a NetBSD kernel in a very long time, that'll be fun$
>> Cross-compile it?  I mean, isnâ??t that what **everybody** does? :-)

Well, not me, but I'm a pretty extreme outlier.  I cross-compile only
in order to get a first binary install on a machine; if it can't
self-host, I don't consider it usable.

But then, I also don't run even vaguely modern NetBSD, and on VAXen
even less so - all my VAX installs are 1.4T-based.  And I don't
currently have any VAX hardware set up and working (all my VAXing in
the last, oh, decade maybe, has been simulated).

> I'm figuring out the cross-compilation tools, build.sh, etc now.  I
> must say the documentation on how to get this set up is slightly
> lacking, for something everybody does. ;)

It is.  But it works remarkably well, especially given the complexity
of the task.  (Even as long ago as 4.0.1, cross-building Just Worked.)
I've just been bringing up a small ARM SoC and I cross-built the world
and have been cross-building kernels.  (It's an unusually challenging
case because, while the manufacturer supported NetBSD and I thus don't
have to write drivers and such, this particular unit has two bad bits
in its RAM; I needed to find them and exclude those pages from use.  So
I was doing a lot of cross-building and netbooting kernels that, for
example, tested memory instead of booting normally.)

My experience has been that build.sh Just Works if you stick to the
things it's documented as supporting - see /usr/src/BUILDING, at least
in the versions I've worked with - but it's hellish to try to wander
outside that envelope.  Perhaps fortunately, I have seldom wanted to
wander; it has mostly been a problem when I want to *native*-build
stuff from /usr/src, but even that has proven fairly easy once I found
USETOOLS=never.

/~\ The ASCII				  Mouse
\ / Ribbon Campaign
 X  Against HTML		mouse%rodents-montreal.org@localhost
/ \ Email!	     7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B