The deadlock is between a CRT thread initialization lock and Windows's process-wide module initialization lock. So if anything is being loaded on demand by the watchdog thread, it's probably locked too (and that could be within the CRT or the OS, so not easy to identify).

I'm still keen to get some version numbers off the build machine, mainly ucrtbased.dll. I'd add code to the build process to just dump them, but I can't get to that for at least a week right now, so if Jeremy can provide it we can rule in/out some possibilities.