[krbdev.mit.edu #5692] KFW: KFWLOGON: avoid missing symbol errors when building with VS 2005

[Jeffrey Altman via RT]

To be very specific about what this revision does, it adds the
bufferoverflowu.lib file to the compile step just as it is done in every
other Makefile.in which is built on Windows.   If there are no symbols
required from the library, the library is ignored.  

The $(SCLIB) variable resolves to the empty string when using the .NET
2003 compiler.

Failure to include this library when building with VS 2005 will result
in a failure during the link step.