message: Use release mode instead of debug mode in the readme
  cc
diff: $ git clone https://github.com/bjorn3/rustc_codegen_cranelift.git
  $ cd rustc_codegen_cranelift
  $ ./prepare.sh # download and patch sysroot src and install hyperfine for benchmarking
  -$ ./test.sh
  +$ ./test.sh --release
  ```
  ## Usage
  @@ -18,13 +18,15 @@ $ ./test.sh
  ### Cargo
  ```bash
  -$ $cg_clif_dir/cargo.sh run
  +$ CHANNEL="release" $cg_clif_dir/cargo.sh run
  ```
  +If you compiled cg_clif in debug mode you should use `CHANNEL="debug"` instead or omit `CHANNEL="release"` completely.
  +
  ### Rustc
  ```bash
  -$ rustc -Cpanic=abort -Zcodegen-backend=$cg_clif_dir/target/debug/librustc_codegen_cranelift.so --sysroot $cg_clif_dir/build_sysroot/sysroot my_crate.rs
  +$ rustc -Cpanic=abort -Zcodegen-backend=$cg_clif_dir/target/release/librustc_codegen_cranelift.so --sysroot $cg_clif_dir/build_sysroot/sysroot my_crate.rs
  ```
  