@LGB-Z: Hi, Lénárt. Nice to meet you here. Please, could you make an arch=ARM11 (BCM2835) for me? I would like to try something out. It is for a "BARE METAL" project.
Let's stick with Gábor, Lénárt is my family name 
It does not make sense to create a new "architecture" unless I (or you) know what to do differently for that architecture ... I mean, I can do that, but without filling the needed code, Makefile changes etc etc etc needed for that given "port" of Xemu, it will result in the same as some other "arch=" (architecture). For "bare metal" you basically want to run something without any OS, etc. For starting point, you must port the whole SDL2 project to that situation. Then you must add your own code to do initialization of the hardware itself you want to run on, providing/implementing some C / POSIX like functions, including implementing file system, time/date/timing stuff, audio/video "drivers" etc. Basically you need to write your own "mini OS", since in case of bare metal, you don't have an already existing underlying infrastructure provided by the OS. So you must do that for yourself. Also, for sure, you need the dedicated toolchain for the given architecture, but that's the most easy part really, the bulk of a "bare metal" project is rather the other stuffs.
What you want to do can be similar to the "Commodore Pi" project for example, I believe, for that project as well, not so much happened since years, since all of the CPU / hardware / etc initialization must be done manually, and the performance somehow is horrible compared to using an OS (as it turned out, it's not so much trivial to set CPU's caches, programming the "chipset" - well in case of Raspberry Pi, it's really a SoC but anyway). So you see ...
Anyway, I had some similar idea as yours here some time ago, but it's really not so easy to do so. Xemu is developed to utilize SDL2 also some common OS functions like filesystem etc. All of these dependencies must be provided first, to be able to run Xemu on it .... (Xemu is not even a "clean" SDL project, ie it used other calls as well than only SDL ones, let it be C standard, or even POSIX, which is provided in case of Windows by the mingw cross-compiler's run-time stuff ...).
But in fact, I already tried to run Xemu on Raspberry Pi (though years before, even before C65/M65 emulation in Xemu ...), it works, but note, that it wasn't a bare metal project, but running on the Raspbian OS (Linux) of Rapsberry Pi (though it worked without X, as SDL2 has support for using framebuffer implementation of the Linux kernel directly, I believe ... or something similar, I can't remember now so much).
If you can create a demonstration to be able to compile some SDL example code (which would compile for Linux / Windows as well without any hack, and on the top of your bare metal project as well - again without any change on the SDL example code of yours), then I think we have a good hope already. But unfortunately I have no time to play with that at level (even though it's quite exciting "game to play"). But, I think, if you can provide a more or less complete test-case where everything already works, and any "standard" SDL app can be run), then it's a much easier project already, and maybe then it's time for me too, to jump in (I have raspberry pi 1 and 3 too, so I can play with that).
(Sein Familienname ist genauso wertvoll wie sein Vorname.)
