sk_GENERAL_SUBTREE_value
subtree = sk_GENERAL_SUBTREE_value(nc->permittedSubtrees, i);
subtree = sk_GENERAL_SUBTREE_value(nc->excludedSubtrees, i);
tree = sk_GENERAL_SUBTREE_value(trees, i);
sub = sk_GENERAL_SUBTREE_value(nc->permittedSubtrees, i);
sub = sk_GENERAL_SUBTREE_value(nc->excludedSubtrees, i);