diff --git a/src/checkbufferoverrun.cpp b/src/checkbufferoverrun.cpp
index de68d84a5..1546367ed 100644
--- a/src/checkbufferoverrun.cpp
+++ b/src/checkbufferoverrun.cpp
@@ -30,7 +30,7 @@
 #include <cstring>
 
 
-#include <stdlib.h>     // <- strtoul
+#include <cstdlib>     // <- strtoul
 
 //---------------------------------------------------------------------------