CLSA-2026-1778112033 avahi: Fix of CVE-2026-24401

CVE-2026-24401: fix avahi-daemon crash on receipt of unsolicited mDNS responses containing self-referencing CNAME records by detecting CNAME loops in lookuphandlecname to prevent uncontrolled recursion and stack exhaustion; also includes two related DoS fixes in the same lookup path from upstream...