Add C2x BOOL_MAX and BOOL_WIDTH to limits.h

[Florian Weimer]

* Joseph Myers:

> C2x adds BOOL_MAX and BOOL_WIDTH macros to <limits.h>.  This patch
> adds them to glibc's <limits.h> for the case when they aren't defined
> by GCC's <limits.h>.
>
> Tested for x86_64.
>
> diff --git a/include/limits.h b/include/limits.h
> index 8195da78a4..29e9b943b9 100644
> --- a/include/limits.h
> +++ b/include/limits.h
> @@ -178,6 +178,18 @@
>  # endif
>  #endif /* Use IEC_60559_BFP_EXT.  */
>  
> +/* The macros for _Bool are not defined by GCC's <limits.h> before GCC
> +   11, or if _GNU_SOURCE is defined rather than enabling C2x support
> +   with -std.  */
> +#if __GLIBC_USE (ISOC2X)
> +# ifndef BOOL_MAX
> +#  define BOOL_MAX 1
> +# endif
> +# ifndef BOOL_WIDTH
> +#  define BOOL_WIDTH 1
> +# endif
> +#endif

Do you know why the width should be 1 and not any other value?

If it has to be 1, irrespective of the storage size, why doesn't the
draft say so?