I’m trying to get my iOS app to build, having just one copy of source. (Using VMware on my Mac, and the 1612 VM.)

The answer at

https://github.com/Microsoft/WinObjC/wiki/FAQ#how-can-i-use-a-vm-on-a-mac-to-develop-a-single-codebase-simultaneously-in-visual-studio-and-xcode

generates

Warning MSB8029 The Intermediate directory or Output directory cannot reside under the Temporary directory as it could lead to issues with incremental build. CocoaLumberjack-iOS C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V140\Microsoft.CppBuild.targets 400