Cargo Features

[dependencies]
hexpatch-keystone-sys = { version = "0.9.4-1", default-features = false, features = ["use_system_keystone", "build_keystone_cmake"] }
default = build_keystone_cmake

The build_keystone_cmake feature is set by default whenever hexpatch-keystone-sys is added without default-features = false somewhere in the dependency tree.

use_system_keystone = pkg-config
build_keystone_cmake default = cmake

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.

pkg-config build use_system_keystone?
cmake build build_keystone_cmake