[Bug c++/70808] Spurious -Wzero-as-null-pointer-constant for nullptr_t

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70808

--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This causes a regression for:

using T = decltype(nullptr);
const constexpr T foo{};

np.cc:2:23: error: ‘(const T)nullptr’ is not a constant expression
 const constexpr T foo{};
                       ^