2011-04-25  Paolo Carlini  <paolo.carlini@oracle.com>

	* include/std/type_traits (struct underlying_type): Add.
	* testsuite/20_util/underlying_type/requirements/typedefs-1.cc: New.
	* testsuite/20_util/underlying_type/requirements/typedefs-2.cc:
	Likewise.
	* testsuite/20_util/underlying_type/requirements/
	explicit_instantiation.cc: Likewise.
	* testsuite/20_util/declval/requirements/1_neg.cc: Adjust dg-error
	line number.

From-SVN: r172944