CMake 3.16 breaks our NSIS installer customizations

We recently updated our CI servers with CMake 3.16rc3 and discovered that the installers produced by the builds were no longer valid. Specifically, we use an NSIS.template.in file in our source repository to customize the installer by adding some new pages to the installer wizard with options to create desktop icons and launch the application after install.

When building with CMake 3.16rc3, these customization do not appear in the resulting installer. When building with 3.15.5, they do appear.

Our project is at https://github.com/highfidelity/hifi but the build process is complex and the NSIS installer requires a number of plugins, so it's not suitable as an easy test project to demonstrate the problem. If I can find the time I will attempt to make a much smaller self-contained example.