message: chore(runtime-c-api) Simplify code.
diff: //! Read runtime errors.
  use libc::{c_char, c_int};
  -use std::cell::RefCell;
  -use std::error::Error;
  -use std::fmt::{self, Display, Formatter};
  -use std::ptr;
  -use std::slice;
  +use std::{
  + cell::RefCell,
  + error::Error,
  + fmt::{self, Display, Formatter},
  + ptr, slice,
  +};
  thread_local! {
  static LAST_ERROR: RefCell<Option<Box<dyn Error>>> = RefCell::new(None);
  