When building with `make MSVC=1 DEBUG=1`, link to `libexpatd.lib`
rather than `libexpat.lib`.
It appears that the `vcpkg` package for "libexpat" has changed and now
creates `libexpatd.lib` for debug mode builds. Previously, both debug
and release builds created a ".lib" with the same basename.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>