Check for proper byteorder functions

[andersk@mit.edu: Add byteorder.h to libmoshcrypto_a_SOURCES]

src/crypto/byteorder.h

@@ -0,0 +1,34 @@
+/*
+    Mosh: the mobile shell
+    Copyright 2012 Keith Winstein
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef BYTEORDER_HPP
+#define BYTEORDER_HPP
+
+#include "config.h"
+
+#ifdef HAVE_HTOBE64
+# include <endian.h>
+#elif HAVE_OSX_SWAP
+# include <libkern/OSByteOrder.h>
+# define htobe64 OSSwapHostToBigInt64
+# define be64toh OSSwapBigToHostInt64
+# define htobe16 OSSwapHostToBigInt16
+# define be16toh OSSwapBigToHostInt16
+#endif
+
+#endif