Imo just use something else. If your build system is really simple just write the Makefiles yourself. If the build system tho needs to be really complex I would use something like meson or scons (Having worked on some gigantic fully GNU make build systems it can get pretty out of hand).
This is all a personal preference thing but cmake in my experience is really non intuitive and a pain to debug. I know it works for a lot of people but I definitely prefer particularly like scons since its python I have a bit easier time understanding what's happening.
If you really need to use cmake, use a debugger like another user commented. There's also a GNU make debugger in case you need to debug makefiles
I don't know the exact details of their setup but I would imagine if they have phones on the ship there's a network they can connect to on the ship that's not their starlink internet.
Aside from being able to possibly identify the starlink waveforms with passive RF surveillance or being able to identify the location of the ship through hacking spacex or their satellites, if they went back and forth between being connected on their phones to the ship network and the internet, their phones could have been compromised, leaving the possibility also of them being a perfect pivot point for hackers interested in exfilling important government secrets.
Overall just very bad opsec for a ship and definitely not a good idea.