diff --git a/src/os_unix.h b/src/os_unix.h
index 0a37763..dd70939 100644
--- a/src/os_unix.h
+++ b/src/os_unix.h
@@ -126,7 +126,7 @@
 #  define SIGDUMMYARG	0, 0, (struct sigcontext *)0
 # else
 #  define SIGPROTOARG	(int)
-#  define SIGDEFARG(s)	(s) int s;
+#  define SIGDEFARG(s)	(s) int s UNUSED;
 #  define SIGDUMMYARG	0
 # endif
 #else