[Bug libstdc++/100146] __cpp_lib_to_chars not defined

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100146

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I suppose this would be OK:

#if _GLIBCXX_HAVE_USELOCALE
# define __cpp_lib_to_chars 201611L
#endif