Didn't get any bites in the main channel --

I've been hoping to get this PR working for darwin -- a python / rust (via maturin / PyO3) project that I think just needs to enable the system feature of the libffi-sys crate (same fix as https://github.com/NixOS/nixpkgs/pull/368102).

Unfortunately in this case the libffi-sys crate is a few dependencies deep, and the parent packages don't expose any feature flags to enable libffi/system (which enables libffi-sys/system):

$ cargo tree -i libffi-sys
libffi-sys v3.2.0
├── deno_ffi v0.190.0
│   └── deno_runtime v0.211.0
│       └── vl-convert-rs v1.7.0 (/private/tmp/nix-build-python3.12-vl-convert-python-1.7.0.drv-0/source/vl-convert-rs)
│           ├── vl-convert v1.7.0 (/private/tmp/nix-build-python3.12-vl-convert-python-1.7.0.drv-0/source/vl-convert)
│           └── vl-convert-python v1.7.0 (/private/tmp/nix-build-python3.12-vl-convert-python-1.7.0.drv-0/source/vl-convert-python)
└── libffi v4.0.0
    └── deno_ffi v0.190.0 (*)

Any suggestions for enabling this feature flag a few dependency layers deep?

if it's not exposed, you can take a dep on libffi-sys directly yourself, and set the feature there

(that's more fragile since you need to use the same version as exists in the dependency, ideally the dependencies would let you pass the system feature)

In reply to @qyliss:fairydust.space
I think you can do it by setting it in the top level Cargo.toml

In reply to @r522:matrix.org

if it's not exposed, you can take a dep on libffi-sys directly yourself, and set the feature there

(that's more fragile since you need to use the same version as exists in the dependency, ideally the dependencies would let you pass the system feature)

In reply to @reckenrode:matrix.org
Can you modify the crate source in rustPlatform.fetchCargoVendor?