(built on guest in /root/df4840; untrimmed tail of the successful build — full command log identical to below)

creating machine/ forwarding header /root/df4840/forwarder_x86_64/include/machine/wchar.h
[... forwarding headers for the kmod build ...]
touch opt_ddb.h
touch opt_drm.h
awk -f dragonfly/tools/makeobjops.awk -- -h dragonfly/kern/bus_if.m
awk -f dragonfly/tools/makeobjops.awk -- -h dragonfly/kern/device_if.m
awk -f dragonfly/tools/makeobjops.awk -- -h dragonfly/bus/pci/pci_if.m
cc  -O2 -pipe -I/usr/src/sys/dev/drm/include -I/usr/src/sys/dev/drm/include/drm -I/usr/src/sys/dev/drm/include/uapi -include /usr/src/sys/dev/drm/kconfig.h -DKBUILD_MODNAME="modeuaf"  -D_KERNEL -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes  -Wmissing-prototypes -Wpointer-arith -Wcast-qual  -Wold-style-definition -Wmissing-include-dirs  -Wno-pointer-sign -Winit-self -Wundef -Wno-unused-but-set-variable -std=gnu11 -Werror -DKLD_MODULE -nostdinc -I/usr/src/sys/dev/drm/include -I/usr/src/sys/dev/drm/include/drm -I/usr/src/sys/dev/drm/include/uapi -I. -Idragonfly -I/root/df4840/forwarder_x86_64/include -Idragonfly/../include -I/usr/include  -Wold-style-declaration -fno-common -ffreestanding -fno-stack-protector -fno-strict-aliasing -fno-strict-overflow -fno-asynchronous-unwind-tables -fno-omit-frame-pointer -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float -mno-fp-ret-in-387 -mindirect-branch=thunk-inline   -c modeuaf.c
cc -Wl,--build-id=sha1 -nostdlib -Wl,--hash-style=sysv   -r -Wl,-d -o modeuaf.ko modeuaf.o
BUILD_OK: -rw-r--r-- 1 root wheel 16192 modeuaf.ko