Build Failure in webrtc-sys Due to Missing video/config/video_encoder_config.h and msvc_spectre_libs Issues on Windows

[termiboros]

Summary

Issue.

I’m encountering a build failure when compiling the Zed project (which depends on webrtc-sys from livekit-rust-sdks at commit 80bb8f4c) on Windows with MSVC. The primary issue is a fatal error C1083 in webrtc-sys because the header video/config/video_encoder_config.h cannot be found. Additionally, I faced an issue with msvc_spectre_libs failing to locate Spectre-mitigated libraries, which I resolved with a workaround, but it may indicate a broader configuration problem. I’m reporting both issues as they occurred during the same build process and may be related to the webrtc-sys setup in this repository.

Environment

OS: Windows 11
Rust Version: stable-x86_64-pc-windows-msvc (default)
1.86-x86_64-pc-windows-msvc (active)
MSVC Version: 14.43.34808 (from Visual Studio Build Tools 2022)
Target: x86_64-pc-windows-msvc
Project: Zed (cloned from https://github.com/zed-industries/zed)
Repository: livekit-rust-sdks (commit 80bb8f4c9112789f7c24cc98d8423010977806a6)
Crate: webrtc-sys v0.3.7, msvc_spectre_libs v0.1.3
Build Command: cargo build --release -

Description

Issue 1:

webrtc-sys Build Failure [C1083: Missing video_encoder_config.h]
When building webrtc-sys the MSVC compiler fails with the following error:

C:\Users\princee\Documents\zed\target\release\build\scratch-ef9d2cc57fe1bfcc\out\livekit_webrtc\livekit\win-x64-release-webrtc-b99fd2c-6\win-x64-release\include\media\base\media_channel.h(60): fatal error C1083: Cannot open include file: 'video/config/video_encoder_config.h': No such file or directory

This error occurs during the compilation of multiple C++ files (e.g., peer_connection.cpp, peer_connection_factory.cpp, rtp_receiver.cpp, rtp_sender.cpp, rtp_transceiver.cpp, webrtc.cpp, frame_cryptor.cpp). The include paths specified in the cc-rs build command are:

-I C:\Users\princee\Documents\zed\target\release\build\webrtc-sys-b6a1ab91a94f6c44\out\cxxbridge\include
-I C:\Users\princee\Documents\zed\target\release\build\webrtc-sys-b6a1ab91a94f6c44\out\cxxbridge\crate
-I ./include
-I C:\Users\princee\Documents\zed\target\release\build\scratch-ef9d2cc57fe1bfcc\out\livekit_webrtc\livekit\win-x64-release-webrtc-b99fd2c-6\win-x64-release\include
-I C:\Users\princee\Documents\zed\target\release\build\scratch-ef9d2cc57fe1bfcc\out\livekit_webrtc\livekit\win-x64-release-webrtc-b99fd2c-6\win-x64-release\include\third_party\abseil-cpp
...

I checked the WebRTC include directory (...\win-x64-release\include), but video/config/video_encoder_config.h is missing or not in the expected video/config subdirectory. This suggests either:

The WebRTC source at commit 80bb8f4c is incomplete.
The webrtc-sys build script (build.rs) is not setting the correct include path for video/config.
A bug in the pinned commit.
Additionally, there are non-fatal warnings:

C:\Users\princee\Documents\zed\target\release\build\scratch-ef9d2cc57fe1bfcc\out\livekit_webrtc\livekit\win-x64-release-webrtc-b99fd2c-6\win-x64-release\include\rtc_base\stream.h(111): warning C4068: unknown pragma 'clang'

These indicate Clang-specific pragmas that MSVC doesn’t recognize, suggesting potential portability issues.

Issue 2: msvc_spectre_libs Failure [Resolved with Workaround]

The msvc_spectre_libs crate (v0.1.3) failed to locate Spectre-mitigated libraries, causing a panic in its build.rs:
No spectre-mitigated libs were found. Please modify the VS Installation to add these.

I resolved this by patching msvc_spectre_libs to hardcode the path to my Spectre libraries:
let spectre_libs = Path::new("C:\\Program Files (x86)\\Microsoft Visual Studio\\2022\\BuildTools\\VC\\Tools\\MSVC\\14.29.30133\\lib\\spectre\\x64");

I applied this patch via [patch.crates-io] in Cargo.toml on zed:

[patch.crates-io] # existing
msvc_spectre_libs = { path = "C:\\Users\\princee\\Documents\\msvc_spectre_libs" }

This allowed webrtc-sys to compile successfully, but the debug output from my patched build.rs (using println!) is not appearing, possibly due to Cargo caching or output suppression.

Reproduce

Step to Reproduce:

1. Clone the Zed repository: git clone https://github.com/zed-industries/zed
2. Navigate to C:\Users<username>\Documents\zed
3. Set up the x64 Native Tools Command Prompt for VS 2022:
   "C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\VC\Auxiliary\Build\vcvars64.bat"
4. Run the build:
   cargo build --release --target x86_64-pc-windows-msvc --verbose
5. Observe the C1083 error for webrtc-sys and (without the patch) the msvc_spectre_libs failure.

Expected Behavior:

• webrtc-sys should compile without missing header errors, with all WebRTC headers (including - - video/config/video_encoder_config.h) available and correctly included.
• msvc_spectre_libs should detect Spectre-mitigated libraries automatically without requiring a hardcoded path.

Actual Behavior

• webrtc-sys fails with C1083 due to missing video_encoder_config.h.
• msvc_spectre_libs fails without a patched build.rs, and debug output is not visible even with the patch.

Suggested Fixes

For webrtc-sys:

• Verify if video/config/video_encoder_config.h is present in the WebRTC source at commit 80bb8f4c. If missing, include it or update to a commit where it’s available.
  Update webrtc-sys/build.rs to include the video/config subdirectory in the cc::Build configuration, e.g.:
  .include("path/to/webrtc/include/video/config")
• Consider suppressing Clang pragma warnings with /wd4068 in build.rs.

For msvc_spectre_libs:

Improve the library detection logic in msvc_spectre_libs to find Spectre libraries [e.g., at C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\VC\Tools\MSVC\14.29.30133\lib\spectre\x64] without hardcoding.
Ensure build script output is visible even when cached.

Additional Context

The Zed project pins webrtc-sys to commit 80bb8f4c. Switching to a newer commit or crates.io version (webrtc-sys = "0.3.7") might resolve the issue but could break Zed’s compatibility.
My MSVC version (14.43.34808) is newer than the Spectre library path (14.29.30133), but the libraries are present and work with the patch.
I’m building in the x64 Native Tools Command Prompt with the LIB environment variable set to include the Spectre library path.

Logs

Logs
Relevant build output:

C:\Users\princee\Documents\zed\target\release\build\scratch-ef9d2cc57fe1bfcc\out\livekit_webrtc\livekit\win-x64-release-webrtc-b99fd2c-6\win-x64-release\include\media\base\media_channel.h(60): fatal error C1083: Cannot open include file: 'video/config/video_encoder_config.h': No such file or directory
cargo:warning=ToolExecError: command did not execute successfully (status code exit code: 2): "C:\\Program Files (x86)\\Microsoft Visual Studio\\2022\\BuildTools\\VC\\Tools\\MSVC\\14.43.34808\\bin\\HostX64\\x64\\cl.exe" ...```

## Request
Request
Could the maintainers confirm if the WebRTC source at commit 80bb8f4c includes video/config/video_encoder_config.h? If not, is there a recommended commit or version of webrtc-sys that resolves this? Additionally, any guidance on improving msvc_spectre_libs detection for Windows MSVC builds would be appreciated. I’m happy to test patches or provide more logs.


### Zed Version and System Specs

tsk. no need zed isn;t even build.

System Specs might be helpful to thee.
CPU:: Intel(R) Xeon(R) Platinum 8370C CPU @ 2.80GHz, 2793 Mhz, 2 Core(s), 4 Logical Processor(s)
OS: Microsoft Windows 11 Pro
Version	10.0.26100 Build 26100
System RAM: 8GB
Disk: SSD. at 125MB/s fixed

[termiboros]

tsk. when shall this issue will fix?

[NewtonChutney]

@SomeoneToIgnore, do you have any update on this issue?
I'm facing the same error

[NewtonChutney]

Gotcha.. the doc is faulty, we need to install this workload along with the SDKs mentioned in the doc.
“Desktop Development with C++” workload

These packages are apparently the minimal config.. when we don't need to compile C/C++..
But, there's a different config required for full C/C++ support, which this scenario likely falls under..

[Daquisu]

This error happens to me when I don't open the correct terminal, as mentioned in the windows docs:

You must initialize your environment variables by first launching the "developer" shell (cmd/powershell) this installation places in the start menu or in Windows Terminal and then compile.

In my case, the full developer shell is Developer PowerShell for VS 2022. Opening with it and trying to cargo build works fine, while with the default terminal I have the exact same error.