diff --git a/src/porting.cpp b/src/porting.cpp
index 10b6fc940..0cc323934 100644
--- a/src/porting.cpp
+++ b/src/porting.cpp
@@ -25,7 +25,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "porting.h"
 
-#if defined(__FreeBSD__)
+#if defined(__FreeBSD__)  || defined(__NetBSD__) || defined(__DragonFly__)
 	#include <sys/types.h>
 	#include <sys/sysctl.h>
 #elif defined(_WIN32)