CVE-2026-56131: fix use-after-free from calling XML_ResumeParser() inside a
handler by adding handler call depth tracking and rejecting re-entrant calls
CVE-2026-56407: fix signed integer overflow of entity textLen in doProlog()
for entity values larger than INT_MAX
CVE-2026-56408: fix integer overflow in copyString() when sizing the
allocation for an over-long encoding name