data.diff_regexes.push_back(pcrecpp::RE(optarg, pcrecpp::UTF8()));
data.diff_regex_names.push_back(diff_regex_name);
if (!diff_regex_name.empty()) {
data.diff_regexes.push_back(pcrecpp::RE(optarg, pcrecpp::UTF8()));
data.diff_regex_names.push_back(diff_regex_name);
if (!diff_regex_name.empty()) {