Update to 1.9.23 — security hardening: - Use O_EXCL with sem_open to prevent semaphore pre-planting attacks - Fix OOB memory access in safein()/safeout() on socket errors - Reject command socket connections from different user namespaces - Use O_NOFOLLOW for PID file to prevent symlink attacks - Open random device with O_CLOEXEC, restrict semaphore to 0600 - Fix stale semaphore recovery after SIGKILL - Fix compilation when NO_COMMAND_MODE is defined