Re: You'd think they'd prioritise current Mac OS support over Win16
It does run on Catalina (caveats below) and you can compile to 64 bit Intel on MacOS.
In fact I have customers using programs supplied by me that do exactly that.
Firstly, FPC is a command line compiler.
FPC does include libraries to compile 64 bit MacOS programs which make API calls to the Cocoa system and so if you are clever enough you can write an FPC program in a text editor which compiles to a MacOS 64 bit Cocoa graphical app. I have compiled example apps myself supplied be people cleverer than me and they do work.
If you are not cleverer than me, then you will need some sort of widget set and maybe an IDE that handles Cocoa for you. I believe that you can do this with Lazarus but I haven't tried it.
What I have tried is TransSkel 5 written by Ingemar Ragnemalm and it does work very nicely.
Unfortunately it isn't really cross platform, so what I do is use fpgui as my widget set. This natively compiles to WIN32 API or to X11. My code will compile and run on Windows, Linux, Raspbian and MacOS, and yes it does run on Catalina, but you need an X server, namely xquartz.
I have been working on a native port of Cocoa for fpgui but I've not done anything with it for nearly a year. I am starting to feel quite guilty about that.
Anyway, my point is that the FPC compiler does support Catalina very well and for gui apps it does support Cocoa. If you aren't into raw Cocoa programming then widget sets and IDEs are available. Cross platform isn't so easy.
I haven't yet figured out how I will handle ARM64 MacOS. That's likely going to be a pain in the @#re and frankly Apple are just a pain constantly changing things. I can write code that works on XP right through to Windows 10 in one hit (though not 10S). I can write Linux code that works on anything with an X11 server in one hit (thanks fpgui) but Apple just have to keep messing about with stuff. Even without the major changes the are constantly depracating API calls and I'm still sore with them that my Macbook Pro 17 with an i7 and a GPU won't run Catalina just because it's the wrong GPU. I don't even want a Mac, it's just for testing customer code.