diff --git a/include/compiler.h b/include/compiler.h
index 5b912d34..ed6a7d14 100644
--- a/include/compiler.h
+++ b/include/compiler.h
@@ -145,6 +145,7 @@
 		typedef char __assert_line_ ## y [(x) ? 1 : -1]; \
 		__assert_line_ ## y _x; \
 		_x[0] = '\0'; \
+		(void)_x; \
 }
 
 #define BUILD_BUG()						do { CTASSERT(0); } while (0)