zephyr: channels require allocatio

Only provide the channel abstraction when allocation has been enabled.

Signed-off-by: David Brown <[email protected]>

Author: d3zd3z

zephyr/src/sync.rs

@@ -15,6 +15,9 @@ use core::{
 use crate::time::Forever;
 use crate::sys::sync as sys;
 
+// Channels are currently only available with allocation.  Bounded channels later might be
+// available.
+#[cfg(CONFIG_RUST_ALLOC)]
 pub mod channel;
 
 pub mod atomic {