Check staticlib name falls back to rust_out

Author: ChrisDenton

tests/run-make/dos-device-input/rmake.rs

@@ -1,9 +1,13 @@
 //@ only-windows
 // Reason: dos devices are a Windows thing
 
-use run_make_support::rustc;
+use std::path::Path;
+
+use run_make_support::{rustc, static_lib_name};
 
 fn main() {
     rustc().input(r"\\.\NUL").crate_type("staticlib").run();
     rustc().input(r"\\?\NUL").crate_type("staticlib").run();
+
+    assert!(Path::new(&static_lib_name("rust_out")).exists());
 }