(MAX_CLIP_RECTS): New define.

(struct _XGC): New member clip_region.
(struct _XGC) [MAC_OSX && USE_ATSUI]: New members n_clip_rects and
clip_rects.

src/macgui.h

@@ -192,6 +192,19 @@ typedef struct _XGC
 
   /* QuickDraw background color.  */
   RGBColor back_color;
+
+#define MAX_CLIP_RECTS 2
+  /* QuickDraw clipping region.  */
+  RgnHandle clip_region;
+
+#if defined (MAC_OSX) && USE_ATSUI
+  /* Number of clipping rectangles used in Quartz 2D drawing.  */
+  int n_clip_rects;
+
+  /* Clipping rectangles used in Quartz 2D drawing.  The y-coordinate
+     is in QuickDraw's.  */
+  CGRect clip_rects[MAX_CLIP_RECTS];
+#endif
 } *GC;
 
 #define GCForeground            (1L<<2)