XML_ExpatVersion /usr/lib/tdom0.8.0/libtdom0.8.0.so Have fun.
is this an upstream issue?
You cannot ignore it in Gentoo if that's what you hoped, this is a breach of policy and a security risk.
fixed in tdom-0.8.2.ebuild. needs test and stabilization. shall tdom-0.8.0-r* be masked?
It is merely a potential security risk, as this version of expat is not prone to any known vulnerabilities. It is sufficient to remove the old version, and keep the new one -- no need to stabilize or handle any further.