FYI: i've had a simh 3900 on a zen2 host running build.sh release the last couple of weeks with all the major fixes and it finally completed successfully. woo. thanks to everyone and espcially Kalvis.My 4000/60 is building since a few days, it's sitting in tools building GCC.
Mine's still running, too :) http://vax.zia.io/status.txt