Cargo Features

libc-nnsdk has no features set by default.

[dependencies]
libc-nnsdk = { version = "0.3.0", features = ["rustc-dep-of-std"] }
rustc-dep-of-std = rustc-std-workspace-core

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

rustc-std-workspace-core rustc-dep-of-std?