"Fetching Boost" happens every time I configure

[rcdailey]

Each time I click "Configure" using CMake GUI (version 3.14.2), I see "Fetching Boost". Either this is doing a download or archive extraction, I can't tell for sure, but it is a very time consuming step. Can you please optimize this so that if an archive or extracted output already exists, you skip the corresponding steps?

[Orphis]

I rarely use CMake GUI, so I've never seen this before. I could expect an issue in FetchContent maybe. I'll have a look after the long holiday weekend here!