Crate system_deps

system-deps lets you write system dependencies in Cargo.toml metadata, rather than programmatically in build.rs. This makes those dependencies declarative, so other tools can read them as well. Then, to declare a dependency on testlib >= 1.2, a conditional dependency on testdata >= 4.5 and a dependency on glib-2.0 >= 2.64 add the following section:

[package.system-deps]
testlib = "1.2"
testdata = { version = "4.5", feature = "use-testdata" }
glib = { name = "glib-2.0", version = "2.64" }

In your build.rs, add:

fn main() {
    system_deps::Config::new().probe().unwrap();
}

Dependency versions can also be controlled using features:

[features]
v1_2 = []
v1_4 = ["v1_4"]

[package.system-deps]
gstreamer = { name = "gstreamer-1.0", version = "1.0", feature-versions = { v1_2 = "1.2", v1_4 = "1.4" }}

In this case the highest version among enabled features will be used.

Structs

Config	Structure used to configure metadata before starting to probe for dependencies
Library	A system dependency

Enums

BuildInternalClosureError	Error used in return value of Config::add_build_internal closures
Error	system-deps errors
Source	From where the library settings have been retrieved