Implement the <tuple> part of C++20 p1032 Misc constexpr bits.

[Ville Voutilainen]

On Wed, 20 Nov 2019 at 11:47, Christophe Lyon
<christophe.lyon@linaro.org> wrote:
>
> On Thu, 14 Nov 2019 at 16:55, Jonathan Wakely <jwakely@redhat.com> wrote:
> >
> > On 09/11/19 02:07 +0000, Smith-Rowland, Edward M wrote:
> > >Here is the <tuple> part of C++20 p1032 Misc constexpr bits.
> > >
> > >Tested on x86_64-linux. OK?
> >
> > OK for trunk, thanks.
> >
>
> Hi,
>
> The new test constexpr_allocator_arg_t.cc fails on arm and aarch64 and
> many other targets according to gcc-testresults.
> Is that expected?

No, that's not expected. Can you give a link to the build log?