Non-coercion fails with LLVM:
"indeed there are multiple proprietary compilers and utilities built on top of LLVM—including Apple's Xcode and NVIDIA's CUDA compiler."
https://lwn.net/Articles/582697/
OpenStack is one of the biggest permissively-licensed free software projects out there:
""" Everyone I know who is deploying OpenStack has forked. Not publicly, but they have. No one can run the mainline code, it’s a disaster, and OpenStack politics of the “Big Tent” are going to make that problem a lot worse. Because everyone has their own fork, very little code is making it back upstream. """