diff --git a/common/lib/compat.cpp b/common/lib/compat.cpp
index 32ae8ea66..de6e29054 100644
--- a/common/lib/compat.cpp
+++ b/common/lib/compat.cpp
@@ -65,6 +65,10 @@ static int json_dumpfd_callback(const char *buffer, size_t size, void *data)
 
 	if (write(*dest, buffer, size) == (ssize_t)size)
 		return 0;
+#else
+	(void)buffer;
+	(void)size;
+	(void)data;
 #endif /* HAVE_UNISTD_H */
 
 	return -1;