Many backends are possible:

- The null backend does not generate code, but is still useful for
  typechecking.

- The jit backend exist for now, but really works only for x86;
  porting it on SPARC and powerPC should not be difficult, though.

- The GCC backend should link directly to GCC.

- The GNU C backend should generate GNU C

- The pretty GNU C backend would emphasize on readable output code.

- The ANSI C backend would generate readable ANSI C and assembly
  files.

- The slim binary backend should generate a compressed version of the
  abstract syntax tree.
