Visual Studio 2015 Ultimate Preview Build Failed

When I try to build the UE4.5 source with Visual Studio 2015 Ultimate Preview It fails after I improved UnrealBuildTool with this code.

public enum WindowsCompiler
{
    /// Visual Studio 2012 (Visual C++ 11.0)
    VisualStudio2012,

    /// Visual Studio 2013 (Visual C++ 12.0)
    VisualStudio2013,

    /// <summary>
    /// Visual Studio 2015 (Visual C++ 14.0)
    /// </summary>
    VisualStudio2015
}

And more…

        int VSVersion;

        switch (Compiler)
        {
            case WindowsCompiler.VisualStudio2012:
                VSVersion = 11;
                break;
            case WindowsCompiler.VisualStudio2013:
                VSVersion = 12;
                break;
            case WindowsCompiler.VisualStudio2015:
                VSVersion = 14;
                break;
            default:
                throw new NotSupportedException("Not supported compiler.");
        }

That won’t work. The dependencies are still only built for 2012 and 2013. What you are trying to do will not be possible.