re PR libstdc++/60587 (debug-mode -std=c++11 vector::insert(pos, begin, end) dereferences begin too eagerly)

	PR libstdc++/60587
	* include/debug/functions.h (_Is_contiguous_sequence): Define.
	(__foreign_iterator): Accept additional iterator. Do not dispatch on
	iterator category.
	(__foreign_iterator_aux2): Likewise. Add overload for iterators
	from different types of debug container. Use _Is_contiguous_sequence
	instead of is_lvalue_reference.
	(__foreign_iterator_aux3): Accept additional iterator. Avoid
	dereferencing past-the-end iterator.
	(__foreign_iterator_aux4): Use const value_type* instead of
	potentially user-defined const_pointer type.
	* include/debug/macros.h (__glibcxx_check_insert_range): Fix comment
	and pass end iterator to __gnu_debug::__foreign_iterator.
	(__glibcxx_check_insert_range_after): Likewise.
	(__glibcxx_check_max_load_factor): Fix comment.
	* include/debug/vector (_Is_contiguous_sequence): Define partial
	specializations.
	* testsuite/23_containers/vector/debug/57779_neg.cc: Remove
	-std=gnu++11 option and unused header.
	* testsuite/23_containers/vector/debug/60587.cc: New.
	* testsuite/23_containers/vector/debug/60587_neg.cc: New.

From-SVN: r208755