Address various rustc warnings

Change-Id: I61bbfcdbbbb9a4795e2c280f70903e1b66a165c9
Signed-off-by: James Kuszmaul <james.kuszmaul@bluerivertech.com>
diff --git a/aos/init.rs b/aos/init.rs
index d02a079..331e74d 100644
--- a/aos/init.rs
+++ b/aos/init.rs
@@ -47,7 +47,7 @@
         Self::parse_with_cpp_flags_from(env::args_os())
     }
 
-    /// Like [`parse_with_cpp_flags`] but read from an iterator.
+    /// Like [`WithCppFlags::parse_with_cpp_flags`] but read from an iterator.
     fn parse_with_cpp_flags_from<I, T>(itr: I) -> Self
     where
         I: IntoIterator<Item = T>,
@@ -128,6 +128,7 @@
         }
     }
 
+    #[allow(dead_code)]
     fn get_option(name: &str) -> String {
         unsafe {
             let name = CString::new(name).expect("Flag may not have NUL");