type_traits (is_function): Support ref-qualified functions.

2013-06-13  Daniel Krugler  <daniel.kruegler@gmail.com>

	* include/std/type_traits (is_function): Support ref-qualified
	functions.
	(is_copy_constructible, is_move_constructible, is_copy_assignable,
	is_move_assignable, is_nothrow_copy_constructible,
	is_nothrow_move_constructible, is_nothrow_copy_assignable,
	is_nothrow_move_assignable): Implement LWG 2196.
	(add_lvalue_reference, add_rvalue_reference, add_pointer): Implement
	LWG 2101.
	(__strip_reference_wrapper<<const reference_wrapper<_Tp>>): Remove,
	unused.
	* testsuite/20_util/add_lvalue_reference/value.cc: Extend.
	* testsuite/20_util/add_rvalue_reference/value.cc: Likewise.
	* testsuite/20_util/decay/requirements/typedefs.cc: Likewise.
	* testsuite/20_util/is_assignable/value.cc: Likewise.
	* testsuite/20_util/is_constructible/value-2.cc: Likewise.
	* testsuite/20_util/is_copy_assignable/value.cc: Likewise.
	* testsuite/20_util/is_copy_constructible/value.cc: Likewise.
	* testsuite/20_util/is_function/value.cc: Likewise.
	* testsuite/20_util/is_move_assignable/value.cc: Likewise.
	* testsuite/20_util/is_move_constructible/value.cc: Likewise.
	* testsuite/20_util/is_nothrow_copy_assignable/value.cc: Likewise.
	* testsuite/20_util/is_nothrow_copy_constructible/value.cc: Likewise.
	* testsuite/20_util/is_nothrow_move_assignable/value.cc: Likewise.
	* testsuite/20_util/is_nothrow_move_constructible/value.cc: Likewise.

	* testsuite/20_util/declval/requirements/1_neg.cc: Adjust dg-error
	line number.
	* testsuite/20_util/make_signed/requirements/typedefs_neg.cc:
	Likewise.
	* testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc:
	Likewise.

From-SVN: r200080