[clang] [clang] Implement `__is_pointer_interconvertible_base_of()` (PR #88473)

[via cfe-commits]

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@@ -1740,7 +1740,7 @@ void is_layout_compatible(int n)
   static_assert(!__is_layout_compatible(void, int));
   static_assert(__is_layout_compatible(void, const void));
   static_assert(__is_layout_compatible(void, volatile void));
-  static_assert(__is_layout_compatible(const int, volatile int));
+  static_assert(__is_layout_compatible(const void, volatile void));
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cor3ntin wrote:

Might be better to that separately as NFC ( with this change, `const int, volatile int` is no longer tested)

https://github.com/llvm/llvm-project/pull/88473