implementing:

- userland
  - argument passing to main function (argc, argv)
- libc
  - print_char
    - requires a 3 parameter syscall to 80h (Linux)
      - requires
        - inline assembly

not implementing:
- libc
  - printf
    - format string only, as replacement for puts
    - vararg required in compiler
    - not type-safe
  - puts
    - requires stdout, which is a FILE structure
  - print_char
    - requires a 3 parameter syscall to 80h (Linux)
      - requires
        - either inline assembly
        - linker and calling convention
- preprocessor
  - have a cat building up the required modules instead
  - needs file operations (at least open, close, read)
  - needs a file system on the host and the destination
    (alternative: have a tape-like file system)
- linker
  - have compilation units needs a linker do build
    an executable