[llvm] Generate an .sframe section with a skeleton header (PR #151223)

[James Henderson via llvm-commits]

================
@@ -50,6 +51,9 @@ class LLVM_ABI MCObjectFileInfo {
   /// Compact unwind encoding indicating that we should emit only an EH frame.
   unsigned CompactUnwindDwarfEHFrameOnly = 0;
 
+  /// SFrame ABI architecture byte
----------------
jh7370 wrote:

```suggestion
  /// SFrame ABI architecture byte.
```

https://github.com/llvm/llvm-project/pull/151223