These members should not be null, but there is little cost and perhaps some
benefit in allowing it.
case PIVOT_VALUE_TEXT:
new->text.local = xstrdup (old->text.local);
new->text.c = (old->text.c == old->text.local ? new->text.local
- : xstrdup (old->text.c));
+ : xstrdup_if_nonnull (old->text.c));
new->text.id = (old->text.id == old->text.local ? new->text.local
: old->text.id == old->text.c ? new->text.c
- : xstrdup (old->text.id));
+ : xstrdup_if_nonnull (old->text.id));
break;
case PIVOT_VALUE_TEMPLATE: