[Patches] PC\config.[hc] changes for Win64

[Guido van Rossum]

> Changes to PC\config.[hc] for Win64. MSVC defines _WINxx to differentiate the
> various windows platforms. Python's MS_WINxx are keyed off of these. Note
> that _WIN32 (and hence MS_WIN32 in Python) are defined on Win32 *and* on
> Win64. This is for compatibility reasons. The idea is that the common case is
> that code specific to Win32 will also work on Win64 rather than being
> specific to Win32 (i.e. there is more the same than different in WIn32 and
> Win64).
> 
> The following modules are specifically excluded in the Win64 build:
> audioop, binascii, imageop, rgbimg. They are advertised as heavily 32-bit
> dependent.
> 
> The patch to config.h looks big but it really is not. These are the effective
> changes:
> - MS_WINxx are keyed off _WINxx
> - SIZEOF_VOID_P is set to 8 for Win64
> - COMPILER string is changed appropriately for Win64

Thanks, Trent!

One thing worries me: if COMPILER is changed, that changes
sys.platform to "win64", right?  I'm sure that will break plenty of
code which currently tests for sys.platform=="win32" but really wants
to test for any form of Windows.  Maybe sys.platform should remain
win32?

--Guido van Rossum (home page: http://www.python.org/~guido/)