The seg faults was my fauilt - I was stupid, absently and careless to mix up a Tcl 9 shell with a Tcl 8.6 linked extension. And not to imediately realize that.
Sorry for the noise.
Thanks for clarifying. I think tdom is great and I must admit I learnt a lot by studying its code. I also think the more extensions, the better for the TCL ecosystem.