Wayland: Return whole output area as work area

Related to #1322.
diff --git a/src/wl_monitor.c b/src/wl_monitor.c
index 2b50b51..fb6b13d 100644
--- a/src/wl_monitor.c
+++ b/src/wl_monitor.c
@@ -170,6 +170,18 @@
         *yscale = (float) monitor->wl.scale;
 }
 
+void _glfwPlatformGetMonitorWorkarea(_GLFWmonitor* monitor, int* xpos, int* ypos, int *width, int *height)
+{
+    if (xpos)
+        *xpos = monitor->wl.x;
+    if (ypos)
+        *ypos = monitor->wl.y;
+    if (width)
+        *width = monitor->modes[monitor->wl.currentMode].width;
+    if (height)
+        *height = monitor->modes[monitor->wl.currentMode].height;
+}
+
 GLFWvidmode* _glfwPlatformGetVideoModes(_GLFWmonitor* monitor, int* found)
 {
     *found = monitor->modeCount;