message: Undo breaking change in C API
diff: //! # }
  //! ```
  -use libc::c_char;
  +use libc::{c_char, c_int};
  use std::cell::RefCell;
  use std::fmt::Display;
  use std::ptr::{self, NonNull};
  @@ -86,10 +86,11 @@ pub(crate) fn take_last_error() -> Option<String> {
  /// # Example
  ///
  /// See this module's documentation to get a complete example.
  +// TODO(Amanieu): This should use size_t
  #[no_mangle]
  -pub extern "C" fn wasmer_last_error_length() -> usize {
  +pub extern "C" fn wasmer_last_error_length() -> c_int {
  LAST_ERROR.with(|prev| match *prev.borrow() {
  - Some(ref err) => err.len() + 1,
  + Some(ref err) => err.len() as c_int + 1,
  None => 0,
  })
  }
  @@ -116,11 +117,12 @@ pub extern "C" fn wasmer_last_error_length() -> usize {
  /// # Example
  ///
  /// See this module's documentation to get a complete example.
  +// TODO(Amanieu): This should use size_t
  #[no_mangle]
  pub unsafe extern "C" fn wasmer_last_error_message(
  buffer: Option<NonNull<c_char>>,
  - length: usize,
  -) -> isize {
  + length: c_int,
  +) -> c_int {
  let buffer = if let Some(buffer_inner) = buffer {
  buffer_inner
  } else {
  @@ -133,6 +135,8 @@ pub unsafe extern "C" fn wasmer_last_error_message(
  None => return 0,
  };
  + let length = length as usize;
  +
  if error_message.len() >= length {
  // buffer is too small to hold the error message
  return -1;
  @@ -150,5 +154,5 @@ pub unsafe extern "C" fn wasmer_last_error_message(
  // accidentally read into garbage.
  buffer[error_message.len()] = 0;
  - error_message.len() as isize + 1
  + error_message.len() as c_int + 1
  }
  