[PATCH] Fix libstdc++/6503

[B. Kosnik]

> I have fixed this PR according to Scott Meyers' guideline about 
> comparison operators as non-member functions (Effective STL, 119): now

Great!

> Ok for trunk and branch?

I think so: this just adds the operators, but they are not instantiated
in the libstdc++.so binary, are they? Thanks for the new test file!

-benjamin


> 2002-05-18  Paolo Carlini  <pcarlini@unitus.it>
> 
>         PR libstdc++/6503
>         * include/bits/stl_deque.h (_Deque_iterator::operator==,
>         operator!=, operator<, operator>, operator>=, operator<=):
>         Make non-member functions, to allow comparing const and
>         non-const iterators in any order.
>         * testsuite/23_containers/deque_operators.cc: New testfile.