Re: [musl] [PATCH v2] prevent from redefining __STDC_UTF_{16,32}__ macros

[Rich Felker <dalias@libc.org>]

On Thu, Jan 25, 2024 at 03:14:40PM +0100, Jules Maselbas wrote:
> Undefine any previous __STDC_UTF_{16,32}__ macros before defining
> them to prenvent any warnings of redefining macros.
> 
> ---
> v2:
>  - changed `#if !define(...)` guard to `#undef`, as suggested by Rich Felker
> 
> I encountered this "issue" trying to compile a program with the -isystem
> option to override toolchain/installed musl headers with one from source.
> 
>  include/stdc-predef.h | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/include/stdc-predef.h b/include/stdc-predef.h
> index af1a2799..5ccd884d 100644
> --- a/include/stdc-predef.h
> +++ b/include/stdc-predef.h
> @@ -7,7 +7,10 @@
>  #define __STDC_IEC_559__ 1
>  #endif
>  
> +#undef __STDC_UTF_16__
>  #define __STDC_UTF_16__ 1
> +
> +#undef __STDC_UTF_32__
>  #define __STDC_UTF_32__ 1
>  
>  #endif
> -- 
> 2.43.0

I merged this, but now gcc warns about undefining them if system
header warnings aren't suppressed. I'm not sure what the justification
is for that... *sigh*

Rich