fixes

constants/src/lib.rs

@@ -1,5 +1,6 @@
 #![doc = include_str!("../README.md")]
 #![deny(missing_docs, reason = "all constants should document what they are")]
+#![no_std] // This can be removed if we eventually need `std`.
 
 mod macros;
 

constants/src/output.rs

@@ -1,5 +1,7 @@
 //! Output related.
 
+use crate::macros::monero_definition_link;
+
 /// The minimum amount of blocks a coinbase output is locked for.
 #[doc = monero_definition_link!(a1dc85c5373a30f14aaf7dcfdd95f5a7375d3623, "/src/cryptonote_config.h", 40)]
 pub const COINBASE_LOCK_WINDOW: usize = 60;

constants/src/rpc.rs

@@ -1,6 +1,6 @@
 //! RPC related.
 
-use std::time::Duration;
+use core::time::Duration;
 
 use crate::macros::monero_definition_link;