Cannot configure with cmake on air-gapped network

I was able to get most dependencies cloned and extracted to the right locations in external, but the way the cmake folder is handled makes it impossible for me to build this on an air-gapped network. I have no other options for reasons I can't really get into so I need a way around it.

The main issue is from the user of FetchContent_MakeAvailable, for this to work, I would need to have another way to include those dependencies in a way that doesn't require an internet connection to work.

Start by inspecting the CMake configuration and the handling of dependencies in the external directory, especially the use of FetchContent_MakeAvailable. Determine how pre-cloned and extracted dependencies could be included without network access. Done means the project can configure and build on an air-gapped network using locally available dependencies.

Written by the indexing model from the issue text.