gtk1/gtk2/gtk3 code will require you shipping gtk(version) on modern linux, not all distros have the legacy libraries.

Apple deprecated carbon (which was a thing when gtk1 was around). I don't think you have an option for this on their ARM hardware.

QT1->N code has the same problem, the older libraries are not shipped on most modern linux.

I do absolutely understand if you're going to do static compiles, that can work around that problem, but that arguement nullifies everything, since you can run/write/execute anything in a turing complete system, if you complain you're just not dedicated enough.