Fix compability issues on Windows

[chenming-wu]

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[chenming-wu]

I think most of them are minor fixes, and they won't affect the structure of the project.

[realthunder]

Can you please elaborate the reason of the changes? Do they cause compilation error? Which compiler do you use?

Also, the flex generated file, any reason you re-generate it?

[chenming-wu]

Hi, yes, I was using Visual Studio 2019 (the latest update). Those changed contents can fix all the compilation errors I encountered.

I didn't know why I generated the flex file, I think it's not related to fixing those compilation errors. I would be happy to remove this committed file if you thought the other commits are acceptable.

[realthunder]

I didn't know why I generated the flex file, I think it's not related to fixing those compilation errors. I would be happy to remove this committed file if you thought the other commits are acceptable.

Yes, please revert that file and try again to see if there is any error.

Also, can you please change SoFCSelectionRoot::PASSTHROUGH to PASS_THROUGH and see if it is okay?