struct string_list_item *string_list_insert(struct string_list *list, const char *string);
struct string_list_item *string_list_insert_at_index(struct string_list *list,
int insert_at, const char *string);
struct string_list_item *string_list_insert(struct string_list *list, const char *string);
struct string_list_item *string_list_insert_at_index(struct string_list *list,
int insert_at, const char *string);