ZeroTierOne/zeroidc/vendor/pkg-config/README.md

pkg-config-rs

Documentation

A simple library meant to be used as a build dependency with Cargo packages in order to use the system pkg-config tool (if available) to determine where a library is located.

You can use this crate directly to probe for specific libraries, or use system-deps to declare all your pkg-config dependencies in Cargo.toml.

This library requires Rust 1.30+.

Example

Find the system library named foo, with minimum version 1.2.3:

extern crate pkg_config;

fn main() {
    pkg_config::Config::new().atleast_version("1.2.3").probe("foo").unwrap();
}

Find the system library named foo, with no version requirement (not recommended):

extern crate pkg_config;

fn main() {
    pkg_config::probe_library("foo").unwrap();
}

External configuration via target-scoped environment variables

In cross-compilation context, it is useful to manage separately PKG_CONFIG_PATH and a few other variables for the host and the target platform.

The supported variables are: PKG_CONFIG_PATH, PKG_CONFIG_LIBDIR, and PKG_CONFIG_SYSROOT_DIR.

Each of these variables can also be supplied with certain prefixes and suffixes, in the following prioritized order:

1. <var>_<target> - for example, PKG_CONFIG_PATH_x86_64-unknown-linux-gnu
2. <var>_<target_with_underscores> - for example, PKG_CONFIG_PATH_x86_64_unknown_linux_gnu
3. <build-kind>_<var> - for example, HOST_PKG_CONFIG_PATH or TARGET_PKG_CONFIG_PATH
4. <var> - a plain PKG_CONFIG_PATH

This crate will allow pkg-config to be used in cross-compilation if PKG_CONFIG_SYSROOT_DIR or PKG_CONFIG is set. You can set PKG_CONFIG_ALLOW_CROSS=1 to bypass the compatibility check, but please note that enabling use of pkg-config in cross-compilation without appropriate sysroot and search paths set is likely to break builds.

Some Rust sys crates support building vendored libraries from source, which may be a work around for lack of cross-compilation support in pkg-config.

License

This project is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in pkg-config-rs by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.