static const std::string env_name("GINAC_RUN_EXPENSIVE_TIMINGS");
if (cc++ == 0) {
char* envvar = std::getenv(env_name.c_str());
static const std::string env_name("GINAC_RUN_EXPENSIVE_TIMINGS");
if (cc++ == 0) {
char* envvar = std::getenv(env_name.c_str());