add submodule sync notice
@@ -68,6 +68,8 @@ Make sure you have Rust and LLVM-10 installed.
> Note for Mac users: you also need `llvm` and `binutils` from Homebrew or MacPort, and to add their binaries to your $PATH
+Run `git submodule update --init` to fetch submodules before build if you haven't add option `--recursive ` when clone code.
+
```bash
cargo build --release
```
