0683dde5d3
cargo-xwin drives the Windows MSVC cross-compile via clang-cl, under which CMake sets MSVC=1 — causing libopus 1.3.1's `if(NOT MSVC)` guards to skip the per-file `-msse4.1` / `-mssse3` COMPILE_FLAGS that its x86 SIMD source files need. Clang-cl (unlike real cl.exe) still honors Clang's target-feature system, so those files then fail to compile with "always_inline function '_mm_cvtepi16_epi32' requires target feature 'sse4.1'" errors across silk/NSQ_sse4_1.c, NSQ_del_dec_sse4_1.c, and VQ_WMat_EC_sse4_1.c. Earlier attempts to fix this downstream (cargo-xwin toolchain file, override.cmake CMAKE_C_COMPILE_OBJECT <FLAGS> replace, CFLAGS env vars) all failed because cargo-xwin rewrites override.cmake from scratch on every `cargo xwin build` invocation and cmake-rs's -DCMAKE_C_FLAGS= assembly happens before toolchain FORCE sets propagate. Fixing it upstream at the source: vendor audiopus_sys 0.2.2 into vendor/audiopus_sys, patch its bundled opus/CMakeLists.txt to introduce an MSVC_CL var (true only when CMAKE_C_COMPILER_ID == "MSVC", i.e. real cl.exe), and flip the eight `if(NOT MSVC)` SIMD guards to `if(NOT MSVC_CL)`. Clang-cl then gets the GCC-style per-file flags and the SSE4.1 sources build cleanly. Also flip the `if(MSVC)` global /arch block at line 445 to `if(MSVC_CL)` so only cl.exe applies /arch:AVX and clang-cl relies purely on per-file flags (no global/per-file mixing). Wire via [patch.crates-io] in the workspace root Cargo.toml; the patch is resolved relative to the workspace root as `vendor/audiopus_sys`. Upstream context: xiph/opus#256, xiph/opus PR #257 (both stale). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
About
audiopus_sys is an FFI-Rust-binding to Opus version 1.3.
Orginally, this sys-crate was made to empower the serenity-crate to build audio features on Windows, Linux, and Mac. However, it's not limited to that.
Everyone is welcome to contribute,
check out the CONTRIBUTING.md for further guidance.
Building
Requirements
If you want to build Opus, you will need cmake.
If you have pkg-config, it will attempt to use that before building.
You can also link a pre-installed Opus, see Pre-installed Opus below.
This crate provides a pre-built binding. In case you want to generate the
binding yourself, you will need Clang,
see Pre-installed Opus below for further
instructions.
Linking
audiopus_sys links to Opus 1.3 and supports Windows, Linux, and MacOS
By default, we statically link to Windows, MacOS, and if you use the
musl-environment. We will link dynamically for Linux except when using
mentioned musl.
This can be altered by compiling with the static or dynamic feature having
effects respective to their names. If both features are enabled,
we will pick your system's default.
Environment variables named LIBOPUS_STATIC or OPUS_STATIC will take
precedence over features thus overriding the behaviour. The value of these
environment variables have no influence of the result: If one of them is set,
statically linking will be picked.
Pkg-Config
By default, audiopus_sys will use pkg-config on Unix or GNU.
Setting the environment variable LIBOPUS_NO_PKG or OPUS_NO_PKG will bypass
probing for Opus via pkg-config.
Pre-installed Opus
If you have Opus pre-installed, you can set LIBOPUS_LIB_DIR or
OPUS_LIB_DIR to the directory containing Opus.
Be aware that using an Opus other than version 1.3 may not work.
Generating The Binding
If you want to generate the binding yourself, you can use the
generate_binding-feature.
Be aware, bindgen requires Clang and its LIBCLANG_PATH
environment variable to be specified.
Installation
Add this to your Cargo.toml:
[dependencies]
audiopus_sys = "0.2"