Can't load linux64.ko module

[Steve Kargl]

Booting a kernel from
%  uname -a
FreeBSD sleepdirt 12.0-CURRENT FreeBSD 12.0-CURRENT #0 r331370: \
  Thu Mar 22 13:41:30 AKDT 2018 \
  kargl at sleepdirt:/usr/obj/usr/src/amd64.amd64/sys/SLEEPDIRT  amd64

gives the following from dmesg

% dmesg | grep linux
link_elf_obj: symbol elf64_linux_vdso_fixup undefined
linker_load_file: /boot/kernel/linux64.ko - unsupported file type

Mine kernel config file contains

options         COMPAT_LINUX32
options         COMPAT_LINUXKPI
options         LINPROCFS

Is something else missing?  A glimpse at /sys/conf/NOTES and
/sys/amd64/conf/GENERIC do not reveal anything obvious.

-- 
Steve