You write an ahead of time compiler to machine code for your language. You write a program that is then compiled to native code. You do a bit of assembler glue

You write an ahead of time compiler to machine code for your language. You write a program that is then compiled to native code. You do a bit of assembler glue to set up an execution environment that your language runtime needs. You link them together, do a bit more glue to turn the result into a bootable disk image. Done. You start out in kernel mode and will have to do a lot of work to bring online a conventional OS-like environment, but from that point on there's nothing really C-like required.