The header defines boost::iterator template, which is an alias for
std::iterator, which is itself deprecated since C++17.
Updated test to avoid testing the definition in C++17 onwards
to avoid failures due to deprecation warnings from libc++-13.
- Update iterator_facade test for #1019
(header change already merged).
- Category of each iterator is reduced to a known category before we try to
find a minimum. Fixes#1517.
- `function_input_iterator` from Dean Michael Berris. Fixes#2893
- Fix typo in `boost/iterator.hpp`. Fixes#3434.
- Always include `add_reference` header in iterator adaptor header.
Did not merge changes for #1427.
[SVN r70709]
