The docs (http://llvm.org/docs/GettingStartedVS.html) indicate that GnuWin32 (not the individual shell/utility/tool dependencies) is needed for testing LLVM with an MSVC build.
GnuWin32 appears to have been last updated in late 2010. Its Wikipedia page indicates that is it unmaintained.
Input regarding alternatives to using GnuWin32 (especially for setting up automated Visual Studio builds) would be much appreciated.