message: Get size of integers using libc
diff: @@ -522,6 +522,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  } else {
  let tp = this.force_ptr(this.read_scalar(args[1])?.not_undef()?)?;
  + let long = this.resolve_path(&["libc", "c_long"])?.ty(*tcx);
  + let time_t = this.resolve_path(&["libc", "time_t"])?.ty(*tcx);
  +
  + let tv_sec_size = this.layout_of(time_t)?.size;
  + let tv_nsec_size = this.layout_of(long)?.size;
  +
  let allocation = this.memory_mut().get_mut(tp.alloc_id)?;
  let mut sign = 1;
  @@ -533,13 +539,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  e.duration()
  });
  - let tv_sec_size = Size::from_bits(64);
  - let tv_nsec_size = Size::from_bits(64);
  -
  allocation.write_scalar(
  tcx,
  tp,
  - Scalar::from_int(sign * (duration.as_secs() as i64), tv_sec_size).into(),
  + Scalar::from_int(sign * (duration.as_secs() as i64), tv_sec_size)
  + .into(),
  tv_sec_size,
  )?;
  