message: Only ship the compiler variable if there are available compilers
diff: @@ -13,6 +13,7 @@ use wasmer_engine_object_file::ObjectFile;
  ///
  /// This is a Wasmer-specific type with Wasmer-specific functions for
  /// manipulating it.
  +#[cfg(feature = "compiler")]
  #[derive(Debug, Copy, Clone)]
  #[repr(C)]
  pub enum wasmer_compiler_t {
  @@ -21,6 +22,7 @@ pub enum wasmer_compiler_t {
  SINGLEPASS = 2,
  }
  +#[cfg(feature = "compiler")]
  impl Default for wasmer_compiler_t {
  fn default() -> Self {
  cfg_if! {
  @@ -72,6 +74,7 @@ impl Default for wasmer_engine_t {
  #[derive(Debug, Default)]
  #[repr(C)]
  pub struct wasm_config_t {
  + #[cfg(feature = "compiler")]
  compiler: wasmer_compiler_t,
  engine: wasmer_engine_t,
  }
  @@ -85,6 +88,7 @@ pub extern "C" fn wasm_config_new() -> Box<wasm_config_t> {
  }
  /// Configure the compiler to use.
  +#[cfg(feature = "compiler")]
  #[no_mangle]
  pub extern "C" fn wasm_config_set_compiler(
  config: &mut wasm_config_t,
  @@ -190,6 +194,7 @@ pub unsafe extern "C" fn wasm_engine_delete(_engine: Option<Box<wasm_engine_t>>)
  pub extern "C" fn wasm_engine_new_with_config(
  config: Box<wasm_config_t>,
  ) -> Option<Box<wasm_engine_t>> {
  + #[allow(dead_code)]
  fn return_with_error<M>(msg: M) -> Option<Box<wasm_engine_t>>
  where
  M: ToString,
  