Add derive-based protocol leaf declarations

src/lib.rs

@@ -11,9 +11,15 @@
 
 #![no_std]
 
-extern crate alloc;
+pub extern crate alloc;
+// Re-export derive macros against a stable `::unshell` path, including when the
+// macros are used inside this crate's own examples and tests.
+#[allow(unused_extern_crates)]
+extern crate self as unshell;
 
 pub mod logger;
 pub mod protocol;
 
+pub use unshell_macros::Leaf;
+
 // pub use ush_obfuscate as obfuscate;