--- configure.ac.orig	2009-08-27 17:37:12.000000000 +0200
+++ configure.ac	2009-09-29 20:32:39.000000000 +0200
@@ -476,7 +476,7 @@ AC_CHECK_HEADERS([fcntl.h limits.h sys/t
 	[AC_MSG_ERROR([Required header file(s) are missing.])])
 
 # If any of these headers are missing, things should still work correctly:
-AC_CHECK_HEADERS([sys/param.h sys/sysctl.h byteswap.h],
+AC_CHECK_HEADERS([sys/param.h sys/sysctl.h byteswap.h sys/endian.h],
 	[], [], [
 #ifdef HAVE_SYS_PARAM_H
 #	include <sys/param.h>
@@ -504,6 +504,25 @@ main(void)
 	])dnl
 fi
 
+if test x$ac_cv_header_sys_endian_h = xyes ; then
+	m4_foreach([FUNC], [bswap16,bswap32,bswap64], [
+		AC_MSG_CHECKING([if FUNC is available])
+		AC_LINK_IFELSE([AC_LANG_SOURCE([
+#include <sys/endian.h>
+int
+main(void)
+{
+	FUNC[](42);
+	return 0;
+}
+		])], [
+			AC_DEFINE(HAVE_[]m4_toupper(FUNC), [1],
+					[Define to 1 if] FUNC [is available.])
+			AC_MSG_RESULT([yes])
+		], [AC_MSG_RESULT([no])])
+
+	])dnl
+fi
 
 ###############################################################################
 # Checks for typedefs, structures, and compiler characteristics.