RUSTFLAGS="-C target-feature=" doesn't seems to be taken into account

[wiiznokes]

I'm building bindings the the rnnoise c library.
Using cargo build, i get this warning:
warning: rnnoise2-sys@0.1.0: 163 | #warning "Only SSE and SSE2 are available. On newer machines, enable SSSE3/AVX/AVX2 using -march= to get better performance"

When using RUSTFLAGS="-C target-feature=+ssse3,+avx,+avx2" cargo build --release, there is still warning.

When using CFLAGS="-march=native" cargo build --release, no warning

[NobodyXu]

Thanks for reporting!

It'd need to be added to RustcCodegenFlags:

cc-rs/src/flags.rs

Line 8 in 6361640

branch_protection: Option<&'a str>,

I'd accept a PR for adding this