It appears that there is a misconfigured CMake file, for gollvm project.
https://github.com/golang/go/issues/41527 - this is my description.
So to be short: there is a confusing warning, not proven by build attempts or release experiments: some linker are reported to no being supported. Even if so - it is not clear what is the case.
Probably updating CMake configs could have more sense, for supporting lld.