[PATCH 1/4] include: Add macro to ignore -Wuser-defined-warnings

[Enze Li]

Hi Nick,

On Tue, Sep 20 2022 at 05:36:05 PM +0100, Nick Clifton wrote:

> Hi Tsukasa,
>
>> +# if __has_warning ("-Wuser-defined-warnings")
>
> I have not seen __has_warning () before.  Is this a new feature of
> recent GCCs and Clang, or am I just behind the times ?
>
> Cheers
>   Nick

I happen to know some info about this function-like macro.  It was first
introduced in 2011.  AFAIK, it is only supported by clang.
More detail, see here[1] for docs and here[2] for implement.

[1] https://clang.llvm.org/docs/LanguageExtensions.html#has-warning
[2] https://github.com/llvm/llvm-project/commit/a35d67dfd927191a16cf24931981d79901938381

Thanks,
Enze