Exclude benches from 'make lint' clippy run

Author: kngwyu

Makefile

@@ -16,7 +16,7 @@ fmt:
 
 clippy:
 	@touch src/lib.rs  # Touching file to ensure that cargo clippy will re-check the project
-	cargo clippy --features=all-stable --all-targets -- \
+	cargo clippy --features=all-stable --tests -- \
 		$(addprefix -D ,${CLIPPY_LINTS_TO_DENY})
 	for example in examples/*; do (cd $$example/; cargo clippy) || exit 1; done