[C++-sig] builtin_converters.hpp using outdated API on win64 builds

[Austin Bingham]

I'm currently trying to build boost-1.45 against python-3.1.3 on win64
(visual studio 2009 sp1). This build is failing because
boost/python/converter/builtin_converters.hpp is using APIs that have
been removed from python3 without checking the python version; at
lines 138 and 144 PyInt_FromLong is being used.

If I understand what's going in that code, the fix is to update line
125 to check the python version. I think we can just add:

  && PY_VERSION_HEX < 0x03000000

to the preprocessor conditional.

I've made this change locally, and it seems to fix things. Does this
seem like the correct fix? If so, how do I get a patch to the right
people (or at least ask them to make this change)?

Austin