rsyslog service fails to start in RHEL 8 and later when compatibility mode is set in SYSLOGD_OPTIONS="-c <number>"

Issue

• rsyslog service will not start
• Rsyslog is exiting with status error = 1
• Rsyslog service failed to start after updating the system from RHEL7 to RHEL8
• rsyslog service unable to start and service status shows below output

 # systemctl status rsyslog.service
   ● rsyslog.service - System Logging Service
      Loaded: loaded (/usr/lib/systemd/system/rsyslog.service; enabled; vendor preset: enabled)
      Active: failed (Result: exit-code) since Wed 2025-04-02 10:01:08 +08; 4s ago
        Docs: man:rsyslogd(8)
              https://www.rsyslog.com/doc/
     Process: 745868 ExecStart=/usr/sbin/rsyslogd -n $SYSLOGD_OPTIONS (code=exited, status=1/FAILURE)
    Main PID: 745868 (code=exited, status=1/FAILURE)
 Apr 02 10:01:08 hostname systemd[1]: rsyslog.service: Main process exited, code=exited, status=1/FAILURE
 Apr 02 10:01:08 hostname systemd[1]: rsyslog.service: Failed with result 'exit-code'.