going back to memset because with complex structures, the static initializer is getting messy:
/code/11930/usr/src/boot/lib/libstand/zfs/zfsimpl.c:1685: warning: missing braces around initializer [-Wmissing-braces]
/code/11930/usr/src/boot/lib/libstand/zfs/zfsimpl.c:1685: warning: (near initialization for 'vtmp.v_childlink') [-Wmissing-braces]
/code/11930/usr/src/boot/lib/libstand/zfs/zfsimpl.c:1685: warning: missing braces around initializer [-Wmissing-braces]
/code/11930/usr/src/boot/lib/libstand/zfs/zfsimpl.c:1685: warning: (near initialization for 'vtmp.v_childlink') [-Wmissing-braces]