On 2023-01-14 17:20, Khem Raj wrote:
> +/* GCC releases before GCC 4.9 had a bug in _Alignof.  See GCC bug 52023
> +<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52023>.
> +   clang versions < 8.0.0 have the same bug.  */
> +#elif (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 \
> +       || (defined __GNUC__ && __GNUC__ < 4 + (__GNUC_MINOR__ < 9) \
> +           && !defined __clang__) \
> +       || (defined __clang__ && __clang_major__ < 8))

We already have two copies of that stuff elsewhere (in lib/stdalign.in.h 
and m4/stdalign.m4), for reasons that currently escape me. Let's not 
balloon the number of copies to three.

I installed the attached smaller patch which should do the trick for C.

Is there a similar problem with C++.