Build protobufs for compact formats

zcash_client_backend/build.rs

@@ -0,0 +1,11 @@
+use protobuf_codegen_pure;
+
+fn main() {
+    protobuf_codegen_pure::run(protobuf_codegen_pure::Args {
+        out_dir: "src/proto",
+        input: &["proto/compact_formats.proto"],
+        includes: &["proto"],
+        customize: Default::default(),
+    })
+    .expect("protoc");
+}