new = xmalloc (sizeof *new);
new->name = xstrdup (old->name);
- new->label = old->label != NULL ? xstrdup (old->label) : NULL;
+ new->label = xstrdup_if_nonnull (old->label);
new->type = old->type;
new->vars = xmemdup (old->vars, old->n_vars * sizeof *old->vars);
new->n_vars = old->n_vars;