@RedTechEngineer @zleap >Non-Linux GNU systems
Yes, GNU systems without Linux exist, as GNU is not a "Linux system".
>non-GNU Linux systems
Linux is not a system - as if you go and install just Linux, it won't run.
>Haiku
That does not use the kernel, Linux.
Although it does use GNU software like glibc;
https://git.haiku-os.org/haiku/tree/License.mdAlthough, Haiku is unacceptable regardless, as it's proprietary software derived from the proprietary BeOS and more proprietary software was added too;
https://git.haiku-os.org/haiku/tree/data/system/data/firmware>Android
Android is not a system that can stand on its own - the buildscripts to compile it only run on GNU/Linux and software for Android is developed on GNU/Linux.
It really sucks bad until you at least install parts of GNU via Termux and it's adb shell seems to be designed for the installation of GNU bash (so you at least have access to a non-terrible shell).
Android is GNU-derived, but happens to not contain any of GNU by default.
>MacOS and Winblows are partially GNU to a not fully known extent (being habitual GPL violators)
macos shipped GPLv2-or-later GNU software in compliance with its licensing, but stopped updating the software when it was upgraded to GPLv3-or-later - as that was too free
windows didn't seem to ship any GNU software - only some LGPLv2.1 libraries - although with the latest "co-pilot" enforcement, unknown amounts of GNU code are being copy-pasted into windows.
microsoft tends to avoid blatantly infringing FSF copyrights in a way that doesn't allow them to simply dismiss a claim, as the FSF would be glad to sue after all.
There also BusyBox/Linux, which is under a GNU license and you need GNU to compile it, but there's not much else.
It's the Linux project that merely supplies a kernel and some tools (util-linux).
Linux would be nowhere and cannot do without GNU, but GNU will do just fine without Linux.