PR libstdc++/77528
	* include/bits/stl_queue.h (queue::c): Add default member initializer.
	(queue::queue()): Add constructor and define as defaulted.
	(queue::queue(_Sequence&&)): Remove default argument.
	(priority_queue::c, priority_queue::comp): Add default member
	initializers.
	(priority_queue::priority_queue()): Add constructor and define as
	defaulted.
	(priority_queue::priority_queue(const _Compare&, _Sequence&&)):
	Remove default argument for first parameter.
	* include/bits/stl_stack.h (stack::c): Add default member initializer.
	(stack::stack()): Add constructor and define as defaulted.
	(stack::stack(const _Sequence&)): Remove default argument.
	* testsuite/23_containers/priority_queue/requirements/
	explicit_instantiation/1.cc: Test explicit instantiation with
	non-DefaultConstructible sequence.
	* testsuite/23_containers/priority_queue/77528.cc: New test.
	* testsuite/23_containers/priority_queue/requirements/
	explicit_instantiation/1_c++0x.cc: Replace with 1_c++98.cc.
	* testsuite/23_containers/queue/77528.cc: New test.
	* testsuite/23_containers/queue/requirements/explicit_instantiation/
	1.cc: Test explicit instantiation with non-DefaultConstructible
	sequence.
	* testsuite/23_containers/queue/requirements/explicit_instantiation/
	1_c++0x.cc: Replace with 1_c++98.cc.
	* testsuite/23_containers/stack/77528.cc: New test.
	* testsuite/23_containers/stack/requirements/explicit_instantiation/
	1.cc: Test explicit instantiation with non-DefaultConstructible
	sequence.
	* testsuite/23_containers/stack/requirements/explicit_instantiation/
	1_c++0x.cc: Replace with 1_c++98.cc.

From-SVN: r244278