The fixes for build with VS2010 breaks the build with our "standard" tool-chain, VS2008

As can be seen from the Windows tinderboxes, and I also see it on my own
machine, the build breaks in cli_ure. climaker.exe, a managed C++ program,
gets an exception:

A first chance exception of type 'System.BadImageFormatException' occurred
in mscorlib.dll

Additional information: Could not load file or assembly 'cli_basetypes' or
one of its dependencies. This assembly is built by a runtime newer than the
currently loaded runtime and cannot be loaded.

I think this is because the managed C++ code in climaker.exe has been
compiled by cl.exe from VS2008, but the cli_basetypes.dll (and other C#
code in LO) has been compiled with the C# compiler from the .NET Framework
4.0.

This is because of change 6b0b50e0ec05a6a5279597a3c1158190969e2de0 to
oowintool which makes it prefer the 4.0 csc.exe. Before the change, it used
to prefer the 3.5 one. I think this needs to be changed to depend on which
MSVC is found... if it is 2010, then only the 4.0 C# compiler can be used,
and if it is 2008, then the 3.5 or 2.0 C# compiler can be used. That helps
at least for me...

--tml