+###############################################################################
+#
+# Check for the XINPUT server extension.
+#
+###############################################################################
+
+have_xinput=no
+with_xinput_req=unspecified
+AC_ARG_WITH(xinput-ext,
+[ --with-xinput-ext Include support for the XInput extension.],
+ [with_xinput="$withval"; with_xinput_req="$withval"], [with_xinput=yes])
+
+HANDLE_X_PATH_ARG(with_xinput, --with-xinput-ext, XINPUT)
+
+if test "$with_xinput" = yes; then
+
+ # first check for Xinput.h
+ AC_CHECK_X_HEADER(X11/extensions/XInput.h, [have_xinput=yes],,
+ [#include <X11/Xlib.h>])
+
+ # if that succeeded, then check for libXi
+ if test "$have_xinput" = yes; then
+ have_xinput=no
+ AC_CHECK_X_LIB(Xi, XListInputDevices,
+ [have_xinput=yes; SAVER_LIBS="$SAVER_LIBS -lXi"],
+ [true], -lXext -lX11)
+ fi
+
+ # if that succeeded, then we've really got it.
+ if test "$have_xinput" = yes; then
+ AC_DEFINE(HAVE_XINPUT)
+ fi
+
+elif test "$with_xinput" != no; then
+ echo "error: must be yes or no: --with-xinput-ext=$with_xinput"
+ exit 1
+fi
+
+