[lld] Enough LLD changes to bootstrap OpenBSD on sparc64 (PR #207609)

[Kirill A. Korinsky via llvm-commits]

catap wrote:

@MaskRay sorry, I used full diff to make this PR which includes OpenBSD specific things. A new version addressed all your remarks, and I have drop that PLT-related changes.

https://github.com/llvm/llvm-project/pull/207609