[Bug c++/88173] `std::numeric_limits<double>::quiet_NaN()` is not constexpr

[gcc@christoph-conrads.name]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88173

--- Comment #1 from Christoph Conrads <gcc@christoph-conrads.name> ---
Created attachment 45075
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45075&action=edit
Code pre-processed with GCC 7.3.0 on Ubuntu 18.04 LTS

This file was created with
$ g++ -Wextra -Wall -std=c++11 -pedantic --save-temps nan.cpp
on Ubuntu 18.04 LTS.