[CMake] Collecting libraries for NSIS installer

[David Cole]

> Definitely getting warmer! It looks like that GetPrerequistes only
> works on an existing target so I'm thinking I would have to set this
> up as a "super" cmake project after the main project is already built?

Right, or as a script that runs at "install" time. It requires an
executable file to analyze, so it can come up with the required DLLs.

D