[client] x11: provide an empty rect region to XPresentPixmap

Providing None informs the comppositor that there is full screen damage,
instead we provide an empty rectangle to prevent this behaviour.

client/displayservers/X11/x11.c

@@ -27,7 +27,6 @@
 #include <string.h>
 #include <unistd.h>
 
-#include <X11/extensions/Xfixes.h>
 #include <X11/extensions/XInput2.h>
 #include <X11/extensions/scrnsaver.h>
 #include <X11/extensions/Xinerama.h>
@@ -89,10 +88,10 @@ static void x11DoPresent(void)
     x11.window,
     x11.presentPixmap,
     x11.presentSerial++,
-    0,    // valid
-    0,    // update
-    -1,    // x_off,
-    -1,    // y_off,
+    x11.presentRegion, // valid
+    x11.presentRegion, // update
+    0,    // x_off,
+    0,    // y_off,
     0,    // target_crtc
     None, // wait_fence
     None, // idle_fence
@@ -519,6 +518,8 @@ static bool x11Init(const LG_DSInitParams params)
   XPresentQueryExtension(x11.display, &x11.xpresentOp, &event, &error);
   x11.presentPixmap = XCreatePixmap(x11.display, x11.window, 1, 1, 24);
   XPresentSelectInput(x11.display, x11.window, PresentCompleteNotifyMask);
+  x11.presentRegion = XFixesCreateRegion(x11.display, &(XRectangle){0}, 1);
+
   XMapWindow(x11.display, x11.window);
   XFlush(x11.display);
 

client/displayservers/X11/x11.h

@@ -26,6 +26,7 @@
 #include <X11/Xlib.h>
 #include <X11/Xatom.h>
 #include <X11/Xutil.h>
+#include <X11/extensions/Xfixes.h>
 
 #include <GL/glx.h>
 
@@ -42,6 +43,7 @@ struct X11DSState
 
   uint32_t presentSerial;
   Pixmap presentPixmap;
+  XserverRegion presentRegion;
   LGEvent * frameEvent;
 
   LGThread * eventThread;