Index: src/nec2cpp.cpp
--- src/nec2cpp.cpp.orig
+++ src/nec2cpp.cpp
@@ -51,6 +51,7 @@
 #include "nec2cpp.h"
 #include "nec_exception.h"
 #include <signal.h>
+#include <stdlib.h>
 #include <vector>
 #include <string>