[compiler-rt] Reapply "[compiler-rt][XRay] Make xray_interface.h C compliant" (PR #141728)

[Jan André Reuter via llvm-commits]

Thyre wrote:

Checked on the same system used to report #141598, and the test is ignored correctly.

```
UNSUPPORTED: XRay-powerpc64le-linux :: TestCases/Posix/patching-unpatching.c (4098 of 4158)
```

@sebastiankreutzer, @MaskRay Can you take another look? Thanks!


https://github.com/llvm/llvm-project/pull/141728