GUAC-865: rdpSettings may not have SupportDisplayControl, even if freerdp/client/disp.h is present.

configure.ac

@@ -480,7 +480,9 @@ if test "x${have_freerdp}" = "xyes"
 then
     AC_CHECK_HEADERS([freerdp/client/disp.h],
                      [AC_DEFINE([HAVE_FREERDP_DISPLAY_UPDATE_SUPPORT],,
-                                [Whether FreeRDP supports the display update channel])],
+                                [Whether FreeRDP supports the display update channel])]
+                     [AC_CHECK_MEMBERS([rdpSettings.SupportDisplayControl],,,
+                                       [[#include <freerdp/freerdp.h>]])],
                      have_disp=no,
                      [#include <winpr/wtypes.h>
                       #include <winpr/collections.h>])

src/protocols/rdp/rdp_disp.c

@@ -20,6 +20,7 @@
  * THE SOFTWARE.
  */
 
+#include "config.h"
 #include "client.h"
 
 #include <freerdp/freerdp.h>
@@ -58,7 +59,9 @@ void guac_rdp_disp_load_plugin(rdpContext* context) {
     PubSub_SubscribeChannelConnected(context->pubSub,
             (pChannelConnectedEventHandler) guac_rdp_disp_channel_connected);
 
+#ifdef HAVE_RDPSETTINGS_SUPPORTDISPLAYCONTROL
     context->settings->SupportDisplayControl = TRUE;
+#endif
 
     /* Add "disp" channel */
     ADDIN_ARGV* args = malloc(sizeof(ADDIN_ARGV));