[Listener] Fix byte order macros for OpenBSD >= 5.6

owlps-listener/owlps-listener.h

@@ -62,11 +62,22 @@
 # else // __BYTE_ORDER
 #  error "This program does not handle strange architectures."
 # endif // __BYTE_ORDER
+/* Non-glibc systems (mostly BSDs at this point).
+ * - OpenBSD 5.6 and higher defines le*toh in <endian.h>. Former versions
+ *   defined letoh* in <sys/types.h>.
+ * - NetBSD, FreeBSD and DragonFly define le*toh in <sys/endian.h>.
+ */
 #else // __GLIBC__
-# include <sys/endian.h>
-# ifdef OpenBSD
-#  define le32toh letoh32
-#  define le16toh letoh16
+# if defined(OpenBSD)
+#  if OpenBSD < 201411 // OpenBSD < 5.6
+#   include <sys/types.h>
+#   define le32toh letoh32
+#   define le16toh letoh16
+#  else // OpenBSD < 5.6
+#   include <endian.h>
+#  endif // OpenBSD < 5.6
+# else // OpenBSD
+#  include <sys/endian.h>
 # endif // OpenBSD
 #endif // __GLIBC__