message: fix(c-api) Remove `rustc` warnings.
diff: @@ -87,6 +87,7 @@ pub extern "C" fn wasm_config_set_engine(config: &mut wasm_config_t, engine: was
  }
  /// cbindgen:ignore
  +#[allow(non_camel_case_types)]
  pub struct wasm_engine_t {
  pub(crate) inner: Arc<dyn Engine + Send + Sync>,
  }
  @@ -170,6 +171,7 @@ pub extern "C" fn wasm_engine_new_with_config(
  // TODO: return useful error messages in failure branches
  cfg_if! {
  if #[cfg(feature = "compiler")] {
  + #[allow(unused_mut)]
  let mut compiler_config: Box<dyn CompilerConfig> = match config.compiler {
  wasmer_compiler_t::CRANELIFT => {
  cfg_if! {
  