diff --git a/tools/binpac/src/pac_scan.ll b/tools/binpac/src/pac_scan.ll
index 95e2475c21..0324ef0aa8 100644
--- a/tools/binpac/src/pac_scan.ll
+++ b/tools/binpac/src/pac_scan.ll
@@ -21,6 +21,7 @@
 #include "pac_type.h"
 #include "pac_utils.h"
 #include <libgen.h>
+#include <errno.h>
 
 int line_number = 1;