re PR libstdc++/54025 (atomic<chrono::duration> won't compile: chrono::duration::duration() is not C++11 compliant)

2012-07-20  Chip Salzenberg  <chip@pobox.com>
	    Jonathan Wakely  <jwakely.gcc@gmail.com>

	PR libstdc++/54025
	* include/std/chrono (duration<>::duration): Fix per C++11.
	* testsuite/20_util/duration/cons/54025.cc: New.
	* testsuite/20_util/duration/cons/constexpr.cc: Adjust.

Co-Authored-By: Jonathan Wakely <jwakely.gcc@gmail.com>

From-SVN: r189711