windows-gnu: Failed to load codegen backend: LoadLibraryExw failed: The specified procedure could not be found. (os error 127)

Expected Behaviour

Build script using spirv-builder runs without errors

Example & Steps To Reproduce

1. Copy rust-toolchain.toml to use rustc nightly-2025-06-23
2. build-dependency spirv-builder = { git = "https://github.com/Rust-GPU/rust-gpu" }
3. cargo build

The build fails with the full error:

    error: couldn't load codegen backend \\?\C:\Users\****\Downloads\fvm2d\target\debug\deps\rustc_codegen_spirv.dll: LoadLibraryExW failed: The specified procedure could not be found. (os error 127) (The specified procedure could not be found. (os error 127)) (retried 5 times)

rustc_codegen_spirv.dll does exist in that location, but the error suggests that some symbol is missing that is attempting to be loaded. I don't know how to get the name of the procedure it wants.

System Info

• Rust: rustc 1.89.0-nightly (be19eda0d 2025-06-22) (the date on this value always seems to be 1 day behind the version specified in rust-toolchain.toml)
• OS: Win11
• GPU: NVIDIA GeForce MX450
• SPIR-V: SPIRV-Tools v2025.2 unknown hash, 2025-05-06T12:14:19+00:00

Inizia riproducendo il fallimento con la versione nightly in rust-toolchain.toml, la dipendenza git spirv-builder e cargo build su Windows 11. Indaga sul motivo per cui rustc_codegen_spirv.dll non può essere caricato e verifica che lo stesso script di build venga completato senza l’errore LoadLibraryExW.