For xwayland gdk/gdkx.h does not work.
Remove the more elaborate gf_display_get_workarea function and use only
the fallback.
--- ./src/working-area.c.orig	2016-02-20 22:38:31.000000000 +0000
+++ ./src/working-area.c	2020-01-07 13:37:47.023817524 +0000
@@ -23,126 +23,11 @@
 */
 
 # include <gdk/gdk.h>
-# include <gdk/gdkx.h>
-# include <X11/Xlib.h>
-# include <X11/Xutil.h>
-# include <X11/Xatom.h>
-
-void get_working_area(GdkScreen* screen, GdkRectangle *rect);
-
-static gboolean gf_display_get_workarea(GdkScreen* g_screen, GdkRectangle *rect) {
-	Atom xa_desktops, xa_current, xa_workarea, xa_type;
-	Display *x_display;
-	Window x_root;
-	guint32 desktops = 0, current = 0;
-	gulong *workareas, len, fill;
-	guchar *data;
-	gint format;
-
-	GdkDisplay *g_display;
-	Screen *x_screen;
-
-	/* get the gdk display */
-	g_display = gdk_display_get_default();
-	if(!g_display)
-		return FALSE;
-
-	/* get the x display from the gdk display */
-	x_display = gdk_x11_display_get_xdisplay(g_display);
-	if(!x_display)
-		return FALSE;
-
-	/* get the x screen from the gdk screen */
-	x_screen = gdk_x11_screen_get_xscreen(g_screen);
-	if(!x_screen)
-		return FALSE;
-
-	/* get the root window from the screen */
-	x_root = XRootWindowOfScreen(x_screen);
-
-	/* find the _NET_NUMBER_OF_DESKTOPS atom */
-	xa_desktops = XInternAtom(x_display, "_NET_NUMBER_OF_DESKTOPS", True);
-	if(xa_desktops == None)
-		return FALSE;
-
-	/* get the number of desktops */
-	if(XGetWindowProperty(x_display, x_root, xa_desktops, 0, 1, False,
-						  XA_CARDINAL, &xa_type, &format, &len, &fill,
-						  &data) != Success)
-	{
-		return FALSE;
-	}
-
-	if(!data)
-		return FALSE;
-
-	desktops = *(guint32 *)data;
-	XFree(data);
-
-	/* find the _NET_CURRENT_DESKTOP atom */
-	xa_current = XInternAtom(x_display, "_NET_CURRENT_DESKTOP", True);
-	if(xa_current == None)
-		return FALSE;
-
-	/* get the current desktop */
-	if(XGetWindowProperty(x_display, x_root, xa_current, 0, 1, False,
-						  XA_CARDINAL, &xa_type, &format, &len, &fill,
-						  &data) != Success)
-	{
-		return FALSE;
-	}
-
-	if(!data)
-		return FALSE;
-
-	current = *(guint32 *)data;
-	XFree(data);
-
-	/* find the _NET_WORKAREA atom */
-	xa_workarea = XInternAtom(x_display, "_NET_WORKAREA", True);
-	if(xa_workarea == None)
-		return FALSE;
-
-	if(XGetWindowProperty(x_display, x_root, xa_workarea, 0, (glong)(4 * 32),
-						  False, AnyPropertyType, &xa_type, &format, &len,
-						  &fill, &data) != Success)
-	{
-		return FALSE;
-	}
-
-	/* make sure the type and format are good */
-	if(xa_type == None || format == 0)
-		return FALSE;
-
-	/* make sure we don't have any leftovers */
-	if(fill)
-		return FALSE;
-
-	/* make sure len divides evenly by 4 */
-	if(len % 4)
-		return FALSE;
-
-	/* it's good, lets use it */
-	workareas = (gulong *)(guint32 *)data;
-
-	rect->x = (guint32)workareas[current * 4];
-	rect->y = (guint32)workareas[current * 4 + 1];
-	rect->width = (guint32)workareas[current * 4 + 2];
-	rect->height = (guint32)workareas[current * 4 + 3];
-
-	/* clean up our memory */
-	XFree(data);
-
-	return TRUE;
-}
 
 void get_working_area(GdkScreen* screen, GdkRectangle *rect)
 {
-	if( !gf_display_get_workarea(screen, rect) )
-	{
-		rect->x = 0;
-		rect->y = 0;
-		rect->width = gdk_screen_width();
-		rect->height = gdk_screen_height();
-	}
+	rect->x = 0;
+	rect->y = 0;
+	rect->width = gdk_screen_width();
+	rect->height = gdk_screen_height();
 }