Vendor dependencies

Let's see how I like this workflow.

vendor/tokio/tests/signal_panic.rs

@@ -0,0 +1,29 @@
+#![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+#![cfg(unix)]
+
+use std::error::Error;
+use tokio::runtime::Builder;
+use tokio::signal::unix::{signal, SignalKind};
+
+mod support {
+    pub mod panic;
+}
+use support::panic::test_panic;
+
+#[test]
+fn signal_panic_caller() -> Result<(), Box<dyn Error>> {
+    let panic_location_file = test_panic(|| {
+        let rt = Builder::new_current_thread().build().unwrap();
+
+        rt.block_on(async {
+            let kind = SignalKind::from_raw(-1);
+            let _ = signal(kind);
+        });
+    });
+
+    // The panic location should be in this file
+    assert_eq!(&panic_location_file.unwrap(), file!());
+
+    Ok(())
+}