diff --git a/src/common.cc b/src/common.cc
index 6bc403a2..5fd3274d 100755
--- a/src/common.cc
+++ b/src/common.cc
@@ -1,3 +1,4 @@
+#include <cstdlib>
 #include <string>
 #include <string.h>
 #include <vips/vips.h>