sk_OPENSSL_CSTRING_new_null
STACK_OF(OPENSSL_CSTRING) *engines = sk_OPENSSL_CSTRING_new_null();
if ((groups = sk_OPENSSL_CSTRING_new_null()) == NULL) {
keymgmt_data.names = sk_OPENSSL_CSTRING_new_null();
propdata->prop_namelist = sk_OPENSSL_CSTRING_new_null();
propdata->prop_valuelist = sk_OPENSSL_CSTRING_new_null();
STACK_OF(OPENSSL_CSTRING) *visited = sk_OPENSSL_CSTRING_new_null();