tc-daemon.c improvements

[NerdAlert2023]

• Suggest doing a double fork to ensure the daemon doesn't reacquire a controlling terminal
• unmask(0) so it resets its file creation mask
• leaking file descriptor
• redirect it to a log file instead of /dev/null. Suggest using syslog().
• recovery for if setsid() fails

[wangbin579]

Thank you very much for your improvement suggestions. I will consider these improvement details.