I've run into the following error installing lustre-zfs dkms on the server. From make.log:

 LD [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/ofd/ofd.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osc/osc_request.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/obdclass/obd_mount.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osc/lproc_osc.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osc/osc_dev.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/obdclass/obd_sysfs.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osc/osc_object.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/obdclass/lu_object.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osc/osc_page.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osc/osc_lock.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/obdclass/dt_object.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osc/osc_io.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/obdclass/cl_object.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osc/osc_quota.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osc/osc_cache.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/obdclass/cl_page.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/obdclass/cl_lock.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/obdclass/cl_io.o

  LD [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osc/osc.o

  CC [M]  /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osd-zfs/osd_handler.o

In file included from /usr/src/zfs-2.0.0/include/sys/arc.h:32,

                 from /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osd-zfs/osd_internal.h:51,

                 from /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osd-zfs/osd_handler.c:52:

/usr/src/zfs-2.0.0/include/sys/zfs_context.h:45:10: fatal error: sys/types.h: No such file or directory

 #include <sys/types.h>

          ^~~~~~~~~~~~~

compilation terminated.

make[6]: *** [scripts/Makefile.build:315: /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osd-zfs/osd_handler.o] Error 1

make[5]: *** [scripts/Makefile.build:556: /var/lib/dkms/lustre-zfs/2.14.0/build/lustre/osd-zfs] Error 2

I've tried running dkms standalone to build this module and run into the same issue. Are there any missing dependencies?