message: Re-introduce std::error::Error implementors.
  Got patched:
  `InitError`.
  `Error`.
  Those were removed in
  Fixes
diff: @@ -91,6 +91,7 @@ use libc::{c_char, c_double, c_float, c_int};
  use libc::{c_uchar, c_ushort, c_void};
  use raw_window_handle::{HasRawWindowHandle, RawWindowHandle};
  use semver::Version;
  +use std::error;
  use std::ffi::{CStr, CString};
  use std::fmt;
  use std::marker::Send;
  @@ -416,6 +417,8 @@ impl fmt::Display for Error {
  }
  }
  +impl error::Error for Error {}
  +
  /// An error callback. This can be supplied with some user data to be passed to
  /// the callback function when it is triggered.
  pub type ErrorCallback<UserData> = Callback<fn(Error, String, &UserData), UserData>;
  @@ -655,6 +658,8 @@ impl fmt::Display for InitError {
  }
  }
  +impl error::Error for InitError {}
  +
  /// Initialization hints that can be set using the `init_hint` function.
  #[derive(Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Debug)]
  pub enum InitHint {
  