[Bug libstdc++/85672] error: redefinition of 'constexpr long double std::abs(long double)'

[danglin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85672

--- Comment #2 from John David Anglin <danglin at gcc dot gnu.org> ---
The config file looks like this:

/* Define if __float128 is supported on this host. */
# define _GLIBCXX_USE_FLOAT128 0
#if !defined(__FLOAT128__) && !defined(__SIZEOF_FLOAT128__)
#undef _GLIBCXX_USE_FLOAT128
#endif

I think __FLOAT128__ and __SIZEOF_FLOAT128__ are defined because we have:

      /* Under HPUX, the __float128 type is a synonym for "long double".  */
      (*lang_hooks.types.register_builtin_type) (long_double_type_node,
                                                 "__float128");