[Bug libstdc++/52765] -std=c++0x requires multilib for non-optimized libstdc++

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52765

--- Comment #14 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The original problem should be fixed long ago, because those functions use the
abi_tag now.