[compiler-rt] [compiler-rt][XRay] Make `xray_interface.h` C compliant (PR #140068)

[Sebastian Kreutzer via llvm-commits]

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@@ -14,20 +14,22 @@
 #ifndef XRAY_XRAY_INTERFACE_H
 #define XRAY_XRAY_INTERFACE_H
 
-#include <cstddef>
-#include <cstdint>
+#include <stddef.h>
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sebastiankreutzer wrote:

To fully preserve the current behaviour as a C++ header, maybe it's a good idea to keep using `cstddef` and `cstdint` if compiled with C++. AFAIK there is not a big difference in practice (e.g., both headers put `size_t` in the global namespace), but it might be safer to ensure we don't run into any issues down the line.  

https://github.com/llvm/llvm-project/pull/140068