Re: Change copyObject() to use typeof_unqual

I wrote:
> $ clang --version
> clang version 21.1.8 (Fedora 21.1.8-4.fc43)

> While this version of clang doesn't like typeof_unqual, it does take
> __typeof_unqual__.  So maybe we were premature to decide that we
> could prefer the typeof_unqual spelling.  I can get it to build
> if I use __typeof_unqual__.

After further experimentation: it will take typeof_unqual with
"-std=c23" ... but, again, we are not passing it that switch,
and the default is evidently some older C version.

            regards, tom lane