diff --git a/configure.ac b/configure.ac
index 11153ea..b07291a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -285,19 +285,21 @@ AC_CHECK_DECL([mach_absolute_time],
      [Define if mach_absolute_time is available.])],
   , [[#include <mach/mach_time.h>]])
 
-AC_CHECK_DECL([htobe64],
-  [AC_DEFINE([HAVE_HTOBE64], [1],
-  [Define if htobe64 and friends exist.])],
+AC_CHECK_DECLS([be64toh, betoh64], [], [],
+  [[#if defined(HAVE_ENDIAN_H)
+#include <endian.h>
+#elif defined(HAVE_SYS_ENDIAN_H)
+#include <sys/types.h>
+#include <sys/endian.h>
+#endif]])
+
+AS_IF([test x"$ac_cv_have_decl_be64toh" != xyes &&
+       test x"$ac_cv_have_decl_betoh64" != xyes],
   [AC_CHECK_DECL([OSSwapHostToBigInt64],
      [AC_DEFINE([HAVE_OSX_SWAP], [1],
         [Define if OSSwapHostToBigInt64 and friends exist.])],
      [AC_MSG_WARN([Unable to find byte swapping functions; using built-in routines.])],
-     [[#include <libkern/OSByteOrder.h>]])],
-  [[#if defined(HAVE_ENDIAN_H)
-#include <endian.h>
-#elif defined(HAVE_SYS_ENDIAN_H)
-#include <sys/endian.h>
-#endif]])
+     [[#include <libkern/OSByteOrder.h>]])])
 
 AC_CHECK_DECL([IP_MTU_DISCOVER],
   [AC_DEFINE([HAVE_IP_MTU_DISCOVER], [1],
diff --git a/src/crypto/byteorder.h b/src/crypto/byteorder.h
index a5f0a47..e5f9baa 100644
--- a/src/crypto/byteorder.h
+++ b/src/crypto/byteorder.h
@@ -35,13 +35,20 @@
 
 #include "config.h"
 
-#ifdef HAVE_HTOBE64
+#if HAVE_DECL_BE64TOH || HAVE_DECL_BETOH64
+
 # if defined(HAVE_ENDIAN_H)
 #  include <endian.h>
 # elif defined(HAVE_SYS_ENDIAN_H)
+#  include <sys/types.h>
 #  include <sys/endian.h>
 # endif
 
+#if !HAVE_DECL_BE64TOH && HAVE_DECL_BETOH64
+#define be64toh betoh64
+#define be16toh betoh16
+#endif
+
 #elif HAVE_OSX_SWAP
 # include <libkern/OSByteOrder.h>
 # define htobe64 OSSwapHostToBigInt64