Add export checking to windows libraries

[PeterJohnson]

Linux libraries are checked for exports of frc:: symbols, but Windows ones are currently not.

[jasondaming]

What is the risk here?

[PeterJohnson]

That the vendor built the Windows libraries such that they statically linked or otherwise override WPILib symbols, which could result in overriding of WPILib behavior/classes and difficult to diagnose issues due to that.