pciutils was re-based to 3.1.7 in RHEL5.6 at the request of some of our hardware partners, in order to add some new hardware support.
That'd explain why I didn't hit it when I was testing previously, we were still on CentOS 5.4 and RHEL 5.5 then so obviously this dependency is new in RHEL 5.6. Wonder if they'd consider it a bug ?
Apparently not. The only bug filed about it (that I have found) is BZ 646884, which reported that kudzu failed to build after the update. The response to that was, "add -lresolv"
--Guy