It seems really unlikely to be related to this issue since I'm pretty sure build-amd64 doesn't get used on XP-4.

From the log it looks like it couldn't clean out and reuse the VS temporary build directory.  Manually cleaning it out and restarting the last build appears to have at least gotten past compiling.

I can't really explain why this was a problem, when I was able to manually remove the directory without error, and couldn't find any stray processes that may have been holding references to the files in that temporary directory.