Hi, I'm facing a similar issue to the one reported here but running on Xcode.
I set DYLD_LIBRARY_PATH on terminal to use a custom version of libswiftCore and was able to run my test app. However, I'm trying to override DYLD_LIBRARY_PATH on Xcode, but for some reason it is not getting the custom path.
I tried setting -toolchain-stdlib-rpath as suggested in this post, but nothing worked for me.
In my example, I added an extension in String.swift with the property "debugMessage". I've created a custom toolchain and compilation works well. The problem is the execution:
I even set the variable as environment value but didn't work either.
Thank you for your help!