vaapisink: fix GstNavigation "key-press" / "key-release" events.

Fix arguments to XkbKeycodeToKeysym() for converting an X11 keycode
to a KeySym. In particular, there is no such Window argument. Also
make sure to check for, and use, the correct <X11/XKBlib.h> header
where that new function is defined. Otherwise, default to the older
XKeycodeToKeysym() function.

configure.ac

@@ -559,6 +559,16 @@ if test "$enable_x11" = "yes"; then
     fi
 fi
 
+dnl Check for XKB library
+HAVE_XKBLIB=0
+if test $USE_X11 -eq 1; then
+    AC_CHECK_HEADERS([X11/XKBlib.h], [HAVE_XKBLIB=1], [:])
+fi
+if test $HAVE_XKBLIB -eq 1; then
+    AC_DEFINE_UNQUOTED([HAVE_XKBLIB], 1,
+        [Defined to 1 if the XKB extension exists.])
+fi
+
 dnl Check for XRandR
 HAVE_XRANDR=0
 if test $USE_X11 -eq 1; then

gst/vaapi/gstvaapisink.c

@@ -218,6 +218,20 @@ gst_vaapisink_backend_drm (void)
 #include <gst/vaapi/gstvaapidisplay_x11.h>
 #include <gst/vaapi/gstvaapiwindow_x11.h>
 
+#if HAVE_XKBLIB
+# include <X11/XKBlib.h>
+#endif
+
+static inline KeySym
+x11_keycode_to_keysym (Display * dpy, unsigned int kc)
+{
+#if HAVE_XKBLIB
+  return XkbKeycodeToKeysym (dpy, kc, 0, 0);
+#else
+  return XKeycodeToKeysym (dpy, kc, 0);
+#endif
+}
+
 /* Checks whether a ConfigureNotify event is in the queue */
 typedef struct _ConfigureNotifyEventPendingArgs ConfigureNotifyEventPendingArgs;
 struct _ConfigureNotifyEventPendingArgs
@@ -387,8 +401,7 @@ gst_vaapisink_x11_handle_events (GstVaapiSink * sink)
         case KeyPress:
         case KeyRelease:
           gst_vaapi_display_lock (display);
-          keysym = XkbKeycodeToKeysym (x11_dpy, x11_win,
+          keysym = x11_keycode_to_keysym (x11_dpy, e.xkey.keycode);
-            e.xkey.keycode, 0, 0);
           if (keysym != NoSymbol) {
             key_str = XKeysymToString (keysym);
           } else {