+
+AC_MSG_CHECKING([whether to build ftd2xx device support])
+AC_MSG_RESULT([$want_ftd2xx_highspeed])
+if test $want_ftd2xx_highspeed != no; then
+AC_MSG_CHECKING([for ftd2xx highspeed device support])
+AC_COMPILE_IFELSE([
+#include "confdefs.h"
+#if IS_WIN32
+#include "windows.h"
+#endif
+#include <stdio.h>
+#include <ftd2xx.h>
+DWORD x = FT_DEVICE_4232H;
+], [
+ AC_DEFINE(BUILD_FTD2XX_HIGHSPEED, [1], [Support FT2232H/FT4232HS with FTD2XX.])
+ build_ftd2xx_highspeed=yes
+], [
+ build_ftd2xx_highspeed=no
+] )
+AC_MSG_RESULT([$build_ftd2xx_highspeed])
+
+if test $want_ftd2xx_highspeed = yes -a $build_ftd2xx_highspeed = no; then
+ AC_MSG_ERROR([You need a newer FTD2XX driver (version 0.4.16 or later).])
+ fi
+fi
+