Hi Alexey -- got VS11 beta here, and pulled your changes into my repo. I see a few failures in test/MSVC/*; I think they are all due to the new linker error LNK2011, which says the precompiled header object must be linked into the final program.
I "fixed" it in a couple of the tests by manually linking in the generated StdAfx.obj, but I think we need to make SCons do it automatically using the PCH construction var -- shouldn't be all that difficult I think. I can help with it if you like.
Do those tests fail for you? Maybe it's just me?
We could also consider omitting the automatic /Yd flag if the MSVC version is 11 or greater, since that flag now gives a deprecation warning.