message: rename null func
diff: @@ -713,7 +713,7 @@ pub fn generate_emscripten_env(globals: &mut EmscriptenGlobals) -> ImportObject
  };
  for null_func_name in globals.null_func_names.iter() {
  - env_ns.insert(null_func_name.as_str(), Func::new(nullfunc_x).to_export());
  + env_ns.insert(null_func_name.as_str(), Func::new(nullfunc).to_export());
  }
  let import_object: ImportObject = imports! {
  @@ -735,7 +735,7 @@ pub fn generate_emscripten_env(globals: &mut EmscriptenGlobals) -> ImportObject
  import_object
  }
  -pub fn nullfunc_x(ctx: &mut Ctx, _x: u32) {
  +pub fn nullfunc(ctx: &mut Ctx, _x: u32) {
  use crate::process::abort_with_message;
  debug!("emscripten::nullfunc_i {}", _x);
  abort_with_message(ctx, "Invalid function pointer called with signature 'i'. Perhaps this is an invalid value (e.g. caused by calling a virtual method on a NULL pointer)? Or calling a function with an incorrect type, which will fail? (it is worth building your source files with -Werror (warnings are errors), as warnings can indicate undefined behavior which can cause this)");
  