[Bug libstdc++/54025] atomic won't compile: chrono::duration::duration() is not C++11 compliant

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54025

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-07-19 
10:20:07 UTC ---
Yes, I think so.  I initially wondered if there was some interaction with PR
53901 but I think that just makes the bug visible, duration's constructor
should be explicitly-defaulted anyway.