message: extern is no longer needed cause macro magic
diff: @@ -59,7 +59,7 @@ fn main() -> Result<()> {
  Ok(())
  }
  -extern "C" fn print_num(n: i32, ctx: &mut vm::Ctx) -> i32 {
  +fn print_num(n: i32, ctx: &mut vm::Ctx) -> i32 {
  println!("print_num({})", n);
  let memory = ctx.memory(0);
  