The code in lib/libzfs/common/libzfs_mount.c already basically handles
the case when libshare is not installed. We just need to not fail in
zfs_init_libshare_impl.  I tested this in lx and things work as
expected. I also tested there trying to set sharenfs and sharesmb on
the delegated dataset. Neither is allowed from within a zone.  The
spew of msgs from a native zone is not ZFS specific. I see the same
spew simply running the share command.