Build fails due to external bindgen dependency in aws-lc-rs (x86 to arm)

[ansemjo]

Description

I am building librespot as part of a buildroot configuration for a Raspberry Pi Zero W and using the current dev commit 1ac238e fails due to the "custom build command for aws-lc-sys v0.21.2".

Error output

The following warnings were emitted during compilation:

warning: CMAKE environment variable set: cmake
warning: Generating bindings - external bindgen. Platform: arm-unknown-linux-gnueabihf

error: failed to run custom build command for `aws-lc-sys v0.21.2`

Caused by:
  process didn't exit successfully: `/dacspot/buildroot-2024.02.5/output/build/librespot-dev/target/release/build/aws-lc-sys-a46c324d9798eef6/build-script-main` (exit status: 101)
  --- stdout
  cargo:rerun-if-env-changed=AWS_LC_SYS_NO_PREFIX
  cargo:rerun-if-env-changed=AWS_LC_SYS_INTERNAL_BINDGEN
  cargo:rerun-if-env-changed=AWS_LC_SYS_EXTERNAL_BINDGEN
  cargo:rerun-if-env-changed=AWS_LC_SYS_NO_ASM
  cargo:rerun-if-env-changed=AWS_LC_SYS_CFLAGS
  cargo:rerun-if-env-changed=AWS_LC_SYS_PREBUILT_NASM
  cargo:rerun-if-env-changed=AWS_LC_SYS_C_STD
  cargo:rerun-if-env-changed=AWS_LC_SYS_CMAKE_BUILDER
  cargo:rerun-if-env-changed=AWS_LC_SYS_STATIC
  cargo:rerun-if-env-changed=CMAKE
  cargo:rerun-if-env-changed=CMAKE
  cargo:warning=CMAKE environment variable set: cmake
  cargo:warning=Generating bindings - external bindgen. Platform: arm-unknown-linux-gnueabihf
  cargo:rerun-if-env-changed=AWS_LC_SYS_INCLUDES

  --- stderr
  bindgen-cli was used. Detected version was: 0.60.1 
  If this is not the latest version, consider upgrading : `cargo install --force --locked bindgen-cli`
  See our User Guide for more information about bindgen:https://aws.github.io/aws-lc-rs/index.html
  Failure invoking external bindgen! 

  bindgen-PARAMS: --prefix-link-name aws_lc_0_21_2_ --allowlist-file .*(/|\\)openssl((/|\\)[^/\\]+)+\.h --allowlist-file .*(/|\\)rust_wrapper\.h --rustified-enum point_conversion_form_t --default-macro-constant-type signed --with-derive-default --with-derive-partialeq --with-derive-eq --raw-line 
  // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
  // SPDX-License-Identifier: Apache-2.0 OR ISC
   --generate functions,types,vars,methods,constructors,destructors /dacspot/buildroot-2024.02.5/output/build/librespot-dev/VENDOR/aws-lc-sys/include/rust_wrapper.h --rust-target 1.59 --output /dacspot/buildroot-2024.02.5/output/build/librespot-dev/target/arm-unknown-linux-gnueabihf/release/build/aws-lc-sys-da45e5a6cee12077/out/bindings.rs --formatter rustfmt -- -I /dacspot/buildroot-2024.02.5/output/build/librespot-dev/VENDOR/aws-lc-sys/include -I /dacspot/buildroot-2024.02.5/output/build/librespot-dev/VENDOR/aws-lc-sys/aws-lc/include
  bindgen-STDOUT: 
  bindgen-STDERR: error: Found argument '--prefix-link-name' which wasn't expected, or isn't valid in this context

  	If you tried to supply `--prefix-link-name` as a value rather than a flag, use `-- --prefix-link-name`

  USAGE:
      bindgen [FLAGS] [OPTIONS] <header> -- <clang-args>...

  For more information try --help

  thread 'main' panicked at /dacspot/buildroot-2024.02.5/output/build/librespot-dev/VENDOR/aws-lc-sys/builder/main.rs:559:5:
  aws-lc-sys build failed. Please enable the 'bindgen' feature on aws-lc-rs or aws-lc-sys.For more information, see the aws-lc-rs User Guide: https://aws.github.io/aws-lc-rs/index.html
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Using a commit before 3e85d77 ("Update hyper-rustls to 0.27.2") or installing bindgen on the host system with cargo install --force --locked bindgen-cli, as suggested by the error message, succeeds.

The message links to https://aws.github.io/aws-lc-rs/platform_support.html and asks to enable the bindgen feature on the crate, though I don't know my way around Rust well enough to figure out how to do that for a dependency of another package.

Possibly related but I'm not sure because the errors are different: #1326, #1346

I also found #1318 but I'm not sure how to integrate that in the buildroot configuration cleanly. Is there a way around this that avoids these additional dependencies on the host?

Version

Current dev branch, since commit 3e85d77.

How to reproduce

I'm sure there is a simpler reproducer but this is the exact environment I'm currently building in (without needing to build all of buildroot first):

• Checkout branch systemd / commit 2f1a221 of dacspot
• Start a Debian 12 container with docker run --rm -it -v "$PWD:/dacspot" -w /dacspot debian:12
• Then within the container:

tar xf buildroot-2024.02.5.tar.gz
cd buildroot-2024.02.5/
make BR2_EXTERNAL=../ dacspot_defconfig
make librespot-rebuild

Host (what you are running building librespot on):

• OS: Linux 6.11.2-arch1-1 --> Docker: Debian 12
• Platform: x86_64, cross-compiling to arm (Raspberry Pi Zero W) within buildroot-2024.02.5
• Cargo: cargo 1.74.1 (ecb9851af 2023-10-18), as far as I can tell

[ansemjo]

Aha! The bindgen-cli is already packaged for buildroot, so (I thought) I just need to add it as a dependency in my package/librespot/librespot.mk:

LIBRESPOT_DEPENDENCIES = host-rust-bindgen

Unfortunately, the packaged version 0.65.1 is still too old and I needed to patch rust-bindgen.{mk,hash} manually. But with RUST_BINDGEN_VERSION = 0.70.1 and an appropriate hash I can now compile librespot all within the buildroot framework.

---

Since my particular problem is now solved, I'll close this issue. I'll leave it up to you if you want to reopen for other cross-compilation use(r)s. ☺️