configure error section (zfs 0.6.5.7 on linux 4.7.1_2)

repro-zfs-builderror.sh

#!/bin/sh
# failing section from configure in /var/lib/dkms/zfs/0.6.5.7/build
export LINUX_OBJ=/usr/src/kernel-headers-4.7.1_2

cat confdefs.h - <<_ACEOF >conftest.c


                                #include <linux/xattr.h>

                                int get(struct inode *ip, const char *name,
                                    void *buffer, size_t size) { return 0; }
                                static const struct xattr_handler
                                    xops __attribute__ ((unused)) = {
                                        .get = get,
                                };

int
main (void)
{


  ;
  return 0;
}

_ACEOF



cat - <<_ACEOF >conftest.h

_ACEOF


mkdir -p build && touch build/conftest.mod.c
echo "obj-m := conftest.o" >build/Makefile
modpost_flag=''

cp conftest.c conftest.h build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build $modpost_flag