[client] wayland: make waitFrame work when not rendering

Implement skipFrame and do various things to wake waitFrame.

client/displayservers/Wayland/shell_libdecor.c

@@ -70,6 +70,7 @@ static void libdecorFrameConfigure(struct libdecor_frame * frame,
     wlWm.needsResize = true;
     wlWm.resizeSerial = configuration->serial;
     app_invalidateWindow();
+    waylandForceRender();
   }
   else
     wlWm.configured = true;

client/displayservers/Wayland/shell_xdg.c

@@ -47,6 +47,7 @@ static void xdgSurfaceConfigure(void * data, struct xdg_surface * xdgSurface,
     wlWm.needsResize  = true;
     wlWm.resizeSerial = serial;
     app_invalidateWindow();
+    waylandForceRender();
   }
   else
   {

client/displayservers/Wayland/wayland.c

@@ -173,6 +173,7 @@ struct LG_DisplayServerOps LGDS_Wayland =
   .glSwapBuffers       = waylandGLSwapBuffers,
 #endif
   .waitFrame           = waylandWaitFrame,
+  .skipFrame           = waylandSkipFrame,
   .guestPointerUpdated = waylandGuestPointerUpdated,
   .setPointer          = waylandSetPointer,
   .grabPointer         = waylandGrabPointer,

client/displayservers/Wayland/wayland.h

@@ -307,3 +307,5 @@ void waylandWindowUpdateScale(void);
 void waylandSetWindowSize(int x, int y);
 bool waylandIsValidPointerPos(int x, int y);
 void waylandWaitFrame(void);
+void waylandSkipFrame(void);
+void waylandForceRender(void);

client/displayservers/Wayland/window.c

@@ -144,3 +144,14 @@ void waylandWaitFrame(void)
   if (callback)
     wl_callback_add_listener(callback, &frame_listener, NULL);
 }
+
+void waylandSkipFrame(void)
+{
+  // If we decided to not render, we must commit the surface so that the callback is registered.
+  wl_surface_commit(wlWm.surface);
+}
+
+void waylandForceRender(void)
+{
+  lgSignalEvent(wlWm.frameEvent);
+}