acl-permissions: Fix on FreeBSD When a directory doesn't have an ACL_TYPE_DEFAULT acl, acl_get_file will return an empty acl, but when trying to set that acl, FreeBSD's acl_set_file will fail with errno == EINVAL. Instead, FreeBSD expects acl_delete_def_file to be used. * lib/acl-internal.c (acl_default_nontrivial): Recognize empty default acls. * lib/set-permissions.c (set_acls): Avoid calling acl_set_file for empty ACL_TYPE_DEFAULT acls.