bsd.kmod.mk still references the now-dead /sys:
.if !defined(S)
.if defined(NETBSDSRCDIR)
S= ${NETBSDSRCDIR}/sys
.elif defined(BSDSRCDIR)
S= ${BSDSRCDIR}/sys
.else
===> S= /sys
Dunno what a decent default is - /usr/src/sys?
- Hubert