Envoy Dynamic Modules Rust SDK Crate Universe Example

This is a minimal Bazel + rules_rust Crate Universe example that depends on Envoy's dynamic modules Rust SDK using the Git dependency style documented by the SDK:

[dependencies]
envoy-proxy-dynamic-modules-rust-sdk = { git = "https://github.com/envoyproxy/envoy", tag = "v1.38.2" }

Crate Universe ingests that Cargo.toml through crate.from_cargo.

The Envoy SDK crate lives under:

source/extensions/dynamic_modules/sdk/rust

Its build script currently reads the ABI header via a parent-directory relative path:

../../abi/abi.h

That path works when building inside the full Envoy repository, where the canonical header exists at:

source/extensions/dynamic_modules/abi/abi.h

However, Crate Universe generates a Bazel external repository rooted at the Rust SDK crate directory. In that generated repository, the surrounding Envoy source tree is not present, so ../../abi/abi.h cannot be resolved by the SDK build script.

Reproduce

bazel build //:example

Expected result: the Envoy SDK build script fails when bindgen tries to read ../../abi/abi.h.

Observed failure:

cargo:rerun-if-changed=../../abi/abi.h

thread 'main' panicked at .../build.rs:27:6:
Unable to generate bindings: NotExist("../../abi/abi.h")