Re: toolchain/58089: MKREPRO isn't really reproductible

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

> Date: Fri, 29 Mar 2024 13:10:00 +0000 (UTC)
> From: Manuel Bouyer <Manuel.Bouyer%lip6.fr@localhost>
> 
> 	cvs co -r netbsd-10 -D "2024-03-26 19:10 UTC" -P src
> 	cd src && ./build.sh -m i386 -P tools kernel=GENERIC

It looks like, for the i386 netbsd-10 autobuilds, we use:

-P -x -N0 -V TMPDIR=/tmp -V BUILD=yes -V MAKECONF="${AB_HOME}/etc/make.conf" -V MKDEBUG=yes

where ${AB_HOME}/etc/make.conf has (unnecessarily, I think):

MKREPRO=yes

I have no idea what BUILD=yes does, and it doesn't seem to be
documented in share/mk/bsd.README (but it is _listed_ there and in
BUILDING.mdoc), but -V MKDEBUG=yes is probably the difference.

We should have this information published somewhere so that others can
verify it.