Martin, what I want to achieve is to ensure that someone can download Python sources and compile them without any modification using a standard install of Windows + Visual Studio 2010 SP1.

I don't really care what is the default compiler used to generate the official binaries, this is a decision that should be taken according to what most people use. But a least the compilation should work easily with the recent and popular VS2010 compiler.

As I said the patch is for the moment a quick and dirty draft: it breaks compilation with VS2008 and assume VS2010. Of course this is not my goal: the final patch should work with existing compilers as well as VS2010.

Which part of the changes do you consider unnecessary?

Concerning the target version: I need to use Python 2.7 internally because our application has not been migrated to Python 3.
I think other people may be in the same case.

I understand there is a feature freeze on this branch (event though the changes in this case are well localized and not intrusive), so I will target primarily Python trunk for the inclusion of patches, but I will also maintain internally my own set of patches for Python 2.7 (and in the wiki for those who are interested).