diff --git a/polkadot/README.adoc b/polkadot/README.adoc
index b6c6bd6108..977f50d803 100644
--- a/polkadot/README.adoc
+++ b/polkadot/README.adoc
@@ -107,7 +107,7 @@ rustup update nightly
 rustup target add wasm32-unknown-unknown --toolchain nightly
 rustup update stable
 cargo install --git https://github.com/alexcrichton/wasm-gc
-sudo apt install cmake pkg-config libssl-dev git
+sudo apt install cmake pkg-config libssl-dev git clang
 ----
 
 Then, grab the Polkadot source code: