I spent some hobby-time yesterday looking into what it will take to port TeXmacs to Guile 2.2, since it has a fast virtual machine and I think it will make TeXmacs much more useable. One of the first differences that I find is that the "lazy catch" thing is no longer present.
I realize that the only real way to do this is going to involve spending more hobby-time on learning the internals of guile-1.8 vs guile-2.2 wrt libguile/throw.[hc] and then the internals of TeXmacs itself, to see what's the right thing to do. But if anyone has a quick answer, or any insight that might help me with that study, please, post it here.