[Bug libstdc++/29366] atomics config for sh is weird

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=29366

--- Comment #12 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Oleg Endo from comment #6)
> Created attachment 34478 [details]
> proposed workaround patch
> 
> There hasn't been any update for PR 53579.  I'd like to propose the attached
> patch as a work around until the CXXFLAGS_FOR_TARGET issues has been
> figured/sorted out.

So it turns out they have been sorted out since GCC 5 but nobody noticed. So
you might want to relook into this.