The build steps were, unpack source, ./configure, make, using default settings on a company machine.

The configure_and_make_output.txt I attached should show the whole ./configure output. The only difference is that I was using xcode 11.0 for that output- the errors and behavior are identical though.

The error only seems to occur when building to a network location. This is most of our user space because we oftentimes do builds across platforms with the same source. Buliding at locations or out of source builds to /tmp or /Users/Shared works fine though. /mathworks is a network location which was originally mounted at root, but now we have it mounted at /System/Volumes/Data/mathworks. From there, all other network locations are available through other mount points. We also have some related symlinks at /System/Volumes/Data. I think I need to see how the network access move to /Systems/Volumes/Data might have changed and broken things for the python build. Likely, something deep in the python build is not working well with our new network setup. I will see if I can debug deeper into setup.py and PyBuildExt.build_extensions() to see if it's not working right with our network setup and to get you a way to reproduce this behavior. It's hard to see exactly how the paths get passed to xcode and the compiler though. I'll see what I can get you.