cmake: fix static build on windows
cmake: fix static build on windows

On Windows, we can make a static build by setting the triple to
x64-windows-static, but due to some issues with cmake we also need to
modify the linker flags and Python definitions.

Signed-off-by: Sean Cross <d7e19930cc1f42c2d0781f4d9e6f1fe5891bf9cf@xobs.io>

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