[compiler-rt] [compiler-rt][AArch64] Rewrite SME routines to all use __aarch64_cpu_features. (PR #119414)

[Sander de Smalen via llvm-commits]

sdesmalen-arm wrote:

> On some platforms that happens automatically via an `__attribute__((constructor))` function, but Darwin and Fuchsia don't, and instead rely on an FMV resolver triggering it.

Is there a technical reason for that or is this just an implementation choice?

https://github.com/llvm/llvm-project/pull/119414