Barebones rust example working in user space.

Requires manually copying the executable over to the image.

rust/lib/mammoth/build.rs

@@ -0,0 +1,18 @@
+use std::env;
+
+fn main() {
+    let mut curr_directory = env::current_dir().unwrap();
+    println!("{:?}", curr_directory);
+    assert!(curr_directory.pop());
+    assert!(curr_directory.pop());
+    assert!(curr_directory.pop());
+
+    curr_directory.push("builddbg");
+    curr_directory.push("zion");
+
+    println!(
+        "cargo:rustc-link-search={}",
+        curr_directory.to_str().unwrap()
+    );
+    println!("cargo:rustc-link-lib=zion_stub");
+}