[Bug libgcc/65281] Lots of macros using non-reserved names in gthr headers

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65281

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Actually HIDE_EXPORTS has been handled as _GLIBCXX_HIDE_EXPORTS for a long time
now.
And UNUSED has also been handled as _GLIBCXX_UNUSED too for a long time (since
2001).

This is all handled by the code in libstdc++/include/Makefile.in which does the
renaming there.

I don't see any references in libstdc++ usage where it places a macro in
non-implementation space.