zfeature_lookup_name
extern int zfeature_lookup_name(const char *, spa_feature_t *);
err = zfeature_lookup_name(fname, NULL);
ret = zfeature_lookup_name(feature, &fid);
VERIFY0(zfeature_lookup_name(feat_name, &feat));
if (zfeature_lookup_name(fname, NULL) != 0) {
VERIFY0(zfeature_lookup_name(fname, &fid));