feat: support building protoc from source (#1)

Author: fmorency

Cargo.lock

@@ -19,6 +19,9 @@ heck = "0.5.0"
 prost = "0.14.1"
 prost-build = "0.14.1"
 prost-types = "0.14.1"
+protobuf-src = { version = "2.1.1", optional = true }
+
 
 [features]
-default = []
+default = []
+build-protoc = ["protobuf-src"] # Build `protoc` from source instead of relying on a system installation

Cargo.toml

@@ -73,6 +73,11 @@ const PROTOS: &[&str] = &[
 ];
 
 fn main() -> Result<()> {
+    #[cfg(feature = "build-protoc")]
+    {
+        println!("build-protoc feature is enabled");
+        env::set_var("PROTOC", protobuf_src::protoc());
+    }
     let out_dir = PathBuf::from(env::var("OUT_DIR").expect("OUT_DIR not set"));
     println!("cargo:rerun-if-changed=proto");