[RFC] libstdc++/5734

[Paolo Carlini]

Hi all,

the first part of this PR is about the extension *member* of the vector class:

    vector::push_back()

which adds a default constructed element at the end.

What should we do?

I suppose we cannot simply erase it (for backward compatibility). Perhaps a
preprocessor-based approach similar to that of _GLIBCPP_RESOLVE_LIB_DEFECTS is
in order here?

Thoughts?

Ciao, Paolo.

P.S. The second part of 5734 is about an extension (is_sorted) already moved to
<ext/algorithm>.