diff --git a/src/core/panic.c b/src/core/panic.c
index d50664cfd..f18c0d9e0 100644
--- a/src/core/panic.c
+++ b/src/core/panic.c
@@ -23,7 +23,7 @@
 void
 nni_show_backtrace(void)
 {
-#if NNG_HAVE_BACKTRACE
+#ifdef NNG_HAVE_BACKTRACE
 	void *frames[50];
 	int   nframes;