[Bug libstdc++/61758] std::chrono::steady_clock::now() no longer exported

[Martin.vGagern at gmx dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61758

--- Comment #1 from Martin von Gagern <Martin.vGagern at gmx dot net> ---
I just read https://gcc.gnu.org/ml/gcc-patches/2013-05/msg01553.html indicating
that this is likely a deliberate ABI breakage for an experimental API. If that
is your official position, feel free to close WONTFIX. Too bad that this kind
of information contained in the email isn't included in the commit message.
Would have saved me a lot of time.