after a security VS2008SP1 had known problems that are extensively
documented in Microsoft's KB971092, KB974479, KB974223 and the blog post
http://blogs.msdn.com/b/windowssdk/archive/2009/08/07/installing-windows-sdk-for-server-2008-v6-1-after-vs2008-sp1-causes-conflicts-with-security-update-kb971092.aspx

The workaround is only needed for insufficiently patched development environments.
This case should not assumed to be normal, so the workaround is now disabled by default.