check_integer(regsub_flags(""), 0);
check_integer(regsub_flags("g"), REGSUB_GLOBAL);
check_integer(regsub_flags("i"), REGSUB_CASE_INDEPENDENT);
check_integer(regsub_flags(""), 0);
check_integer(regsub_flags("g"), REGSUB_GLOBAL);
check_integer(regsub_flags("i"), REGSUB_CASE_INDEPENDENT);