cc  -O2 -pipe   -D_KERNEL -Wall -Wredundant-decls ... -DKLD_MODULE -nostdinc ... -c dm_target_flakey.c
cc -Wl,--build-id=sha1 -nostdlib -Wl,--hash-style=sysv -r -Wl,-d -o dm_target_flakey.ko dm_target_flakey.o
MODULE_BUILD_EXIT=0
(Installed to /boot/kernel/dm_target_flakey.ko, kldload dm_target_flakey)