I don't understand why anyone would use ld or gold in 2022. Every distro has shipped lld for years and it links in less than seconds. It's a default to not break compatibility, not because it's good ; makes as much sense to use as ed(1). For reference on a 8C/16T CPU from 2016 an llvm initial build is ~10-12 minutes here.. not instant but not the end of the world either.
lld is not 100% compatible with ld; switching to it usually works, but occasionally breaks the build of some software. That's especially true for complex cases involving linker scripts and unusual binary layouts with various sections. (Those cases also tend to be hard to debug.)
I for one maintain the official toolchains for QNX. I've been trying to port LLVM, and it's not possible to bootstrap LLVM using LLVM because it hasn't been ported yet.
I don't understand, LLVM would be on the host machine under some Linux or Windows on x86 where the development happens, not on the QNX hardware anyways, no ? Unless for some reason one would want to port Mesa to have LLVMPIPE or something like this, but I have a hard time imagining the use case.
My experience with QNX is with it used for automotive stuff, so everything was cross-compiled from normal Linux systems. The little bit of work I did with it did really not make me think that this was an useable workstation OS (although the speed was extremely appreciable)
