pkgconf_fragment_filter
pkgconf_fragment_filter(client, &filtered_list, &unfiltered_list, filter_fn, NULL);
pkgconf_fragment_filter(client, &filtered_list, &unfiltered_list, filter_cflags, NULL);
pkgconf_fragment_filter(client, &filtered_list, &unfiltered_list, filter_libs, NULL);
PKGCONF_API void pkgconf_fragment_filter(const pkgconf_client_t *client, pkgconf_list_t *dest, pkgconf_list_t *src, pkgconf_fragment_filter_func_t filter_func, void *data);