PR libstdc++/59548
	* include/debug/safe_base.h (_Safe_sequence_base): Define copy
	constructor to prevent it being implicitly defined as deleted, but
	do not copy anything.
	* include/debug/safe_unordered_base.h (_Safe_unordered_container_base):
	Define copy and move constructors similar to _Safe_sequence_base's.
	* testsuite/23_containers/unordered_map/59548.cc: New.

From-SVN: r207059