Check for interval_ms.

configure.ac

@@ -244,6 +244,10 @@ AC_CHECK_LIB([freerdp-codec], [freerdp_image_convert],
              [RDP_LIBS="$RDP_LIBS -lfreerdp-codec"],
              [have_freerdp=no])
 
+# FreeRDP-specific structure members
+AC_CHECK_MEMBERS([rdpSvcPlugin.interval_ms],
+                 [[#include <freerdp/utils/svc_plugin.h>]])
+
 # FreeRDP-specific headers
 AC_CHECK_HEADERS([freerdp/locale/keyboard.h])
 

src/protocols/rdp/guac_rdpsnd/rdpsnd_service.c

@@ -92,8 +92,10 @@ void guac_rdpsnd_process_connect(rdpSvcPlugin* plugin) {
     audio_stream* audio = (audio_stream*)
         plugin->channel_entry_points.pExtendedData;
 
+#ifdef RDPSVCPLUGIN_INTERVAL_MS
     /* Update every 10 ms */
     plugin->interval_ms = 10;
+#endif
 
     /* Log that sound has been loaded */
     guac_client_log_info(audio->client, "guacsnd connected.");