According to https://bugzilla.redhat.com/show_bug.cgi?id=1955045 this is actually a latent bug in hexchat? So I can modify my karma to +1 if the patch from that BZ is applied to hexchat in F33 (also needed in F34, already in rawhide).
This doesn't appear to fix the problem I reported in #1639043, but it also doesn't make it any worse, and seems to otherwise work okay.
This has the same regression as 4.2.3-200.fc22 (which I unfortunately didn't update to until yesterday) relative to 4.1.10-200.fc22 - boot hangs for a very long time, then displays:
"systemd-udevd: worker  /devices/pci0000:00/0000:04.0/0000:02.0 is taking a long time"
(I think 0000:02.0 is a mistaken reference to my 82576 card at 0000:02:00.0, which then fails to be bound to the igb driver as it was in kernel 4.1.10-200 and previous).
Since it's not new, (4.2.3-200 has the same problem and is already in stable) this shouldn't hold up this kernel, but I need to report it somewhere.