Don't decorate windows with an empty shape.

Some clients (e.g. Wine) set windows to have an empty XShape bounding region.
They may also set those windows to have decorations.  In that situation,
quartz-wm was producing weird small, black windows for what should be
invisible windows.

Reviewed-by: Jeremy Huddleston <jeremyhu@apple.com>
(cherry picked from commit 901809d)

src/x-input.m

@@ -689,7 +689,8 @@ static void x_event_configure_request(XConfigureRequestEvent *e) {
     if (w == nil || w->_id != e->window || e->kind != ShapeBounding)
         return;
 
-    w->_shaped = YES;
+    w->_shaped = e->shaped ? YES : NO;
+    w->_shaped_empty = (e->shaped && (e->width <= 0 || e->height <= 0));
 
     [w update_shape];
 }

src/x-window.h

@@ -63,6 +63,7 @@
 
     unsigned _reparented :1;
     unsigned _shaped :1;
+    unsigned _shaped_empty :1;
     unsigned _removed :1;
     unsigned _deleted :1;
     unsigned _focused :1;

src/x-window.m

@@ -420,7 +420,7 @@ - (void) place_window {
 }
 
 -(xp_frame_class) get_xp_frame_class {
-    if(_fullscreen)
+    if(_fullscreen || _shaped_empty)
         return _frame_behavior | XP_FRAME_CLASS_DECOR_NONE;
     return _frame_behavior | _frame_decor;
 }
@@ -918,6 +918,7 @@ - (void) update_shaped
                         &wws, &hws, &clip, &xbs, &ybs, &wbs, &hbs);
 
     _shaped = bounding ? YES : NO;
+    _shaped_empty = (bounding && (wws <= 0 || hws <= 0));
 }
 
 - (void) update_shape:(X11Rect)or