I built -current with:

/etc/mk.conf:

CPUFLAGS = -mv8 -mtune=supersparc

kernel config file:

makeoptions     CPUFLAGS="-mv8 -mtune=supersparc"

This fixes the sh dumping core problem but raises the question of how NetBSD
should be compiled on sun4m and probably sun4d.

I did not test this, but, GENERIC or a custom kernel that is not built
with "options SUN4M" as the sole architecture option my work.

At least, there needs to be complete documentation of the "problem".
-- 
Rick Kelly	rmk@rmkhome.com
		<http://www.rmkhome.com/>
		<http://rkba.rmkhome.com/> - the right to keep and bear arms
		<http://wolf.rmkhome.com/> - firearm forums