Working on native Windows x64 version of PostgreSQL

Hi everyone.

For those who have seen my other thread, I have decided to take the
plunge: I am going to try to get PostgreSQL to compile as a native
Windows x64 application (so that it will be able to interface with x64
DLLs) and I will contribute my changes to the community.

As you know, many of the extra postgres features rely on external
libraries available from gnuwin32, so these must also be converted to
x64 DLLs or they won't work. I will be starting small, disabling all
these extra features and only trying to build the core functionality.

I plan to work on this in a few stages, submitted as work in progress
patches, because I think this will require a lot of changes. The
first stage is very simple though; I will be modifying the Perl
scripts in the src/tools/msvc directory to support the x64 compiler.
I am using Microsoft Visual C 2008, but I will try to ensure
everything works with Visual C 2005 (no previous versions have an x64
compiler, so there are only 2 platforms to support).

While this is the simplest change, it may need the most review. I am
a good C programmer but I barely know Perl. That has its advantages;
it will ensure I stick to the style currently used since I have no
other habits.

-Ken