[clang] [lld] [llvm] [lld] Add support for sdata8 for FDE CIE (PR #174508)

[Fangrui Song via cfe-commits]

MaskRay wrote:

There are clang and llvm MC changes, so applying just the `[lld]` tag could be misleading. I would only llvm change in this patch and extract clang and lld changes to separate patches.
If you are proposing a driver option `clang -flarge-fde-encoding`,  it's best to have coordination with GCC folks.

https://github.com/llvm/llvm-project/pull/174508