GUAC-849: Check for presence of AudioPlayback setting in FreeRDP settings struct.

configure.ac

@@ -373,6 +373,7 @@ then
     have_freerdp=yes
     legacy_freerdp_extensions=no
     rdpsettings_interface=unknown
+    rdpsettings_audioplayback=yes
     rdpsettings_fastpath=yes
     freerdp_interface=unknown
     event_interface=unknown
@@ -602,6 +603,11 @@ then
                          [rdpsettings_fastpath=no],
                          [[#include <freerdp/freerdp.h>]])
 
+        # Legacy interface may not have AudioPlayback settings
+        AC_CHECK_MEMBERS([rdpSettings.audio_playback],,
+                         [rdpsettings_audioplayback=no],
+                         [[#include <freerdp/freerdp.h>]])
+
     elif test "x${rdpsettings_interface}" = "xunknown"; then
         AC_MSG_WARN([
   --------------------------------------------
@@ -618,6 +624,12 @@ if test "x${have_freerdp}" = "xyes" -a "x${rdpsettings_fastpath}" = "xyes"; then
               [Whether the rdpSettings structure has FastPath settings])
 fi
 
+# Activate audio playback settings if present
+if test "x${have_freerdp}" = "xyes" -a "x${rdpsettings_audioplayback}" = "xyes"; then
+    AC_DEFINE([HAVE_RDPSETTINGS_AUDIOPLAYBACK],,
+              [Whether the rdpSettings structure has AudioPlayback settings])
+fi
+
 # Check if the type CHANNEL_ENTRY_POINTS_FREERDP exists, if not define it to CHANNEL_ENTRY_POINTS_EX
 if test "x${have_freerdp}" = "xyes"
 then

src/protocols/rdp/rdp_settings.c

@@ -109,9 +109,13 @@ void guac_rdp_push_settings(guac_rdp_settings* guac_settings, freerdp* rdp) {
 
     /* Audio */
 #ifdef LEGACY_RDPSETTINGS
+#ifdef HAVE_RDPSETTINGS_AUDIOPLAYBACK
     rdp_settings->audio_playback = guac_settings->audio_enabled;
+#endif
 #else
+#ifdef HAVE_RDPSETTINGS_AUDIOPLAYBACK
     rdp_settings->AudioPlayback = guac_settings->audio_enabled;
+#endif
 #endif
 
     /* Security */