Contents:
1) VC6 support
2) VC70 support

1) STLport is a multiplatform implementation of C++ STL; see
http://www.stlport.org
---------------------------------------------------------

Our hack in a nutshell.

By undefining __STL_NO_CLASS_PARTIAL_SPECIALIZATION in
stlport/config/stl_msvc.h
the iterator_traits are enabled.

the flag
CGAL_LIMITED_ITERATOR_TRAITS_SUPPORT
is used to disable the parts of code that rely on partial
specialization.

This does not resolve the problem of defining iterator_traits
for pointer types.
For this, the macro
CGAL_DEFINE_ITERATOR_TRAITS_POINTER_SPEC(T)
should be used to provide this for pointers to T.
For many builtin types, this is done in
stlport/stl_iterator_base.h

Presentltly, the flag __STL_DEBUG is turned on
for all this to work. 
__STL_DEBUG is switched on for the iterators of std::vector.
Without, these iterators are plain C pointers. With this
flag, they are implemented as class and iterator_traits works fine.

**** added 15/9/99:
__STL_DEBUG is now off. It does not help dealing with
std::vector iterators, as it turned out.

**** added 11/10/99;
introduced vector class by Geert-Jan. Its vector
iterators are not pointers; this removes the necessity to
use CGAL_DEFINE_ITERATOR_TRAITS_POINTER_SPEC(T) for
all T's for which vector<T> is present.
(Naturally, T* could be used somewhere else in the code, and
hence CGAL_DEFINE_ITERATOR_TRAITS_POINTER_SPEC(T) would be still
needed in this case).

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2) VC7.0 native STL needs the same treatment of iterator_traits
for pointer types as VC6. The type  iterator_traits is by itself
defined OK.
 
So CGAL_DEFINE_ITERATOR_TRAITS_POINTER_SPEC(T) is still there,
(file vc7/stl_iterator_base.h)
but instead of STLport the native STL is used (it's considerably updated
w.r.t. VC6 STL).

File vc7/iterator contains also some fixes for <algorithm> header.
(extra overloads for functions _Iter_cat, _Dist_type, _Val_type).