Cargo Features

[dependencies]
cargo-sysroot = { version = "0.8.1", default-features = false, features = ["structopt"] }
default = structopt

The structopt feature is set by default whenever cargo-sysroot is added without default-features = false somewhere in the dependency tree.

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.

structopt default

Required by the binary