shim-client: make dependency on ttrpc-codegen as optional

Now we have feature "generate_bindings" for shim-client, and crate
ttrpc-codegen is used only when feature "generate_bindings" is enabled.
So mark ttrpc-codegen as optional.

Signed-off-by: Liu Jiang <gerry@linux.alibaba.com>

crates/shim-client/Cargo.toml

@@ -15,11 +15,11 @@ protobuf = "2.23.0"
 ttrpc = "0.5.2"
 
 [build-dependencies]
-ttrpc-codegen = "0.2"
+ttrpc-codegen = { version = "0.2", optional = true }
 
 [features]
 # In current implementation we check in all generated TTRPC code because of the following Rust limitations:
 # - `include!` doesn't handle well .rs files with attributes: https://github.com/rust-lang/rust/issues/18810
 # - `cargo publish` will complain on modified `src` directory if it's modified from `build.rs` - https://github.com/rust-lang/cargo/issues/5073
 # - There is now way to include the whole module from `OUT_DIR`, not just individual files.
-generate_bindings = []
+generate_bindings = ["ttrpc-codegen"]

crates/shim-client/build.rs

@@ -19,6 +19,7 @@
 use std::fs;
 use std::io::Write;
 use std::path::Path;
+#[cfg(feature = "generate_bindings")]
 use ttrpc_codegen::{Codegen, ProtobufCustomize};
 
 #[cfg(not(feature = "generate_bindings"))]

crates/shim-client/src/shim/events_ttrpc.rs

@@ -1,4 +1,4 @@
-// This file is generated by ttrpc-compiler 0.4.0. Do not edit
+// This file is generated by ttrpc-compiler 0.4.1. Do not edit
 // @generated
 
 // https://github.com/Manishearth/rust-clippy/issues/702

crates/shim-client/src/shim/shim_ttrpc.rs

@@ -1,4 +1,4 @@
-// This file is generated by ttrpc-compiler 0.4.0. Do not edit
+// This file is generated by ttrpc-compiler 0.4.1. Do not edit
 // @generated
 
 // https://github.com/Manishearth/rust-clippy/issues/702