[Bug libstdc++/69450] [6 Regression] libstdc++-v3/include/math.h:66:1 2: error: 'constexpr bool std::isnan(double)' conflicts with a previous declaration

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69450

--- Comment #15 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Amker, if you're talking about aarch64-*-*gnu* then that's not this bug
(because this is about HP-UX). I assume you're using glibc from git, in which
case see 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69413#c2