My claws-mail hang has now expanded into a gtk2 hang, and it seems
to be specific to running on an Intel i9-9900K, it never happened
on my old haswell system, but now if I install a fedora 31
virtual machine from scratch and run claws-mail in the new VM,
it hangs there as well.
Also hanging is the "config" dialog in gkrellm. The clock and
all the graphs stop as soon as I try to bring up config the
first time. Once I've created it, it comes up quickly on
subsequent requests, so whatever is going on seems to be
happening during the initial construction of a gtk2 window.