Macro parse_metadata 

macro_rules! parse_metadata {
    () => { ... };
}

Parse Components.toml at compile time and return the dependency metadata.

Delegates to parse_components_toml! which searches for Components.toml starting from the calling crate’s directory.

Returns &'static [(&'static str, &'static [&'static str])] where each element is (component_name, &[dep1, dep2, ...]).