diff --git a/src/lisp/error.h b/src/lisp/error.h
index 7f95870..7577cdf 100644
--- a/src/lisp/error.h
+++ b/src/lisp/error.h
@@ -98,3 +98,5 @@
 void ereport(struct error err);
 
 void edebug(struct error err, char *file, int line, const char *func, const char *why);
+
+#define UNUSED(val) (void)(val)