[clang] [clang] Ignore GCC 11 `[[malloc(x)]]` attribute (PR #68059)

[Aaron Ballman via cfe-commits]

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@@ -289,6 +289,11 @@ Bug Fixes to Compiler Builtins
 Bug Fixes to Attribute Support
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+- Clang now emits a warning instead of an error when using the one or two
+  argument form of GCC 11's ``__attribute__((malloc(deallocator)))``
+  or ``__attribute__((malloc(deallocator, ptr-index)))``
+  (`#51607 <https://github.com/llvm/llvm-project/issues/51607>`).
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AaronBallman wrote:

```suggestion
  (`#51607 <https://github.com/llvm/llvm-project/issues/51607>`_).
```

https://github.com/llvm/llvm-project/pull/68059