Standardise and require safety comments in vmbase.

Bug: 290018030
Test: m vmbase_example_bin
Change-Id: Ic5704d6cd9b2a4090fa9758d7a65a56e83c4286c
diff --git a/vmbase/src/lib.rs b/vmbase/src/lib.rs
index 7e47968..e490faa 100644
--- a/vmbase/src/lib.rs
+++ b/vmbase/src/lib.rs
@@ -15,6 +15,8 @@
 //! Basic functionality for bare-metal binaries to run in a VM under crosvm.
 
 #![no_std]
+#![deny(unsafe_op_in_unsafe_fn)]
+#![deny(clippy::undocumented_unsafe_blocks)]
 
 extern crate alloc;