[clang] [llvm] [OpenMP] Emit aggregate kernel prototypes and remove libffi dependency (PR #186261)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> This will break compatibility with existing binaries targetting x86_64. They're probably not used that much for anything serious, but is this a concern?

Yeah, I'm hoping that the actual use of this is narrow enough that no one will notice. Otherwise it's impossible to accomplish its intended goal while being backwards compatible.

https://github.com/llvm/llvm-project/pull/186261