The --with-sdl2 flag is critical. After compilation, run bochs from the terminal. It will now recognize SDL.
Bochs does not statically bundle the SDL library within its own binary by default. It relies on "shared libraries" provided by the operating system. If you attempt to run a pre-compiled Bochs binary that was built against SDL, or if you are compiling it yourself without the development headers, the system will fail to initialize the display. Bochs Display Library Sdl Not Available
If this guide helped you, consider contributing to the Bochs project or the SDL library to support open-source emulation. The --with-sdl2 flag is critical