Avoid using RegionInit() because of empty rects

It creates an invalid region if given an empty rect. Fortunately
RegionInitBoxes() handles that just fine, so use that instead.

unix/xserver/hw/vnc/vncHooks.c

   screen_box.x2 = pScreen->width;
   screen_box.y2 = pScreen->height;
 
-  RegionInit(&screen_rgn, &screen_box, 1);
+  RegionInitBoxes(&screen_rgn, &screen_box, 1);
 
   dx = pWin->drawable.x - ptOldOrg.x;
   dy = pWin->drawable.y - ptOldOrg.y;
   box.x2 = w ? (box.x1 + w) : (pWin->drawable.x + pWin->drawable.width);
   box.y2 = h ? (box.y1 + h) : (pWin->drawable.y + pWin->drawable.height);
 
-  RegionInit(&reg, &box, 0);
+  RegionInitBoxes(&reg, &box, 1);
   RegionIntersect(&reg, &reg, &pWin->clipList);
 
   (*pScreen->ClearToBackground) (pWin, x, y, w, h, generateExposures);
     box.y1 = max(pDst->pDrawable->y + yDst, 0);
     box.x2 = box.x1 + width;
     box.y2 = box.y1 + height;
-    RegionInit(&changed, &box, 0);
+    RegionInitBoxes(&changed, &box, 1);
 
     box.x1 = 0;
     box.y1 = 0;
     box.x2 = pScreen->width;
     box.y2 = pScreen->height;
-    RegionInit(&fbreg, &box, 0);
+    RegionInitBoxes(&fbreg, &box, 1);
 
     RegionIntersect(&changed, &changed, &fbreg);
 
     fbbox.y1 = 0;
     fbbox.x2 = pScreen->width;
     fbbox.y2 = pScreen->height;
-    RegionInit(&fbreg, &fbbox, 0);
+    RegionInitBoxes(&fbreg, &fbbox, 1);
 
     RegionIntersect(changed, changed, &fbreg);
 
     box.y1 += pDst->pDrawable->y;
     box.x2 += pDst->pDrawable->x;
     box.y2 += pDst->pDrawable->y;
-    RegionInit(&changed, &box, 0);
+    RegionInitBoxes(&changed, &box, 1);
 
     box.x1 = 0;
     box.y1 = 0;
     box.x2 = pScreen->width;
     box.y2 = pScreen->height;
-    RegionInit(&fbreg, &box, 0);
+    RegionInitBoxes(&fbreg, &box, 1);
 
     RegionIntersect(&changed, &changed, &fbreg);
 
     box.y1 += pDst->pDrawable->y;
     box.x2 += pDst->pDrawable->x;
     box.y2 += pDst->pDrawable->y;
-    RegionInit(&changed, &box, 0);
+    RegionInitBoxes(&changed, &box, 1);
 
     box.x1 = 0;
     box.y1 = 0;
     box.x2 = pScreen->width;
     box.y2 = pScreen->height;
-    RegionInit(&fbreg, &box, 0);
+    RegionInitBoxes(&fbreg, &box, 1);
 
     RegionIntersect(&changed, &changed, &fbreg);
 
     box.y1 += pDst->pDrawable->y;
     box.x2 += pDst->pDrawable->x;
     box.y2 += pDst->pDrawable->y;
-    RegionInit(&changed, &box, 0);
+    RegionInitBoxes(&changed, &box, 1);
 
     box.x1 = 0;
     box.y1 = 0;
     box.x2 = pScreen->width;
     box.y2 = pScreen->height;
-    RegionInit(&fbreg, &box, 0);
+    RegionInitBoxes(&fbreg, &box, 1);
 
     RegionIntersect(&changed, &changed, &fbreg);
 
     box.y1 += pDst->pDrawable->y;
     box.x2 += pDst->pDrawable->x;
     box.y2 += pDst->pDrawable->y;
-    RegionInit(&changed, &box, 0);
+    RegionInitBoxes(&changed, &box, 1);
 
     box.x1 = 0;
     box.y1 = 0;
     box.x2 = pScreen->width;
     box.y2 = pScreen->height;
-    RegionInit(&fbreg, &box, 0);
+    RegionInitBoxes(&fbreg, &box, 1);
 
     RegionIntersect(&changed, &changed, &fbreg);
 
   box.x2 = box.x1 + w;
   box.y2 = box.y1 + h;
 
-  RegionInit(&reg, &box, 0);
+  RegionInitBoxes(&reg, &box, 1);
   RegionIntersect(&reg, &reg, pGC->pCompositeClip);
 
   (*pGC->ops->PutImage) (pDrawable, pGC, depth, x, y, w, h, leftPad, format,
     box.x2 = box.x1 + w;
     box.y2 = box.y1 + h;
 
-    RegionInit(&dst, &box, 0);
+    RegionInitBoxes(&dst, &box, 1);
   }
 
   RegionIntersect(&dst, &dst, pGC->pCompositeClip);
     box.x2 = box.x1 + w;
     box.y2 = box.y1 + h;
 
-    RegionInit(&src, &box, 0);
+    RegionInitBoxes(&src, &box, 1);
 
     if ((pSrc->type == DRAWABLE_WINDOW) &&
         RegionNotEmpty(&((WindowPtr)pSrc)->clipList)) {
   box.x2 = box.x1 + w;
   box.y2 = box.y1 + h;
 
-  RegionInit(&reg, &box, 0);
+  RegionInitBoxes(&reg, &box, 1);
   RegionIntersect(&reg, &reg, pGC->pCompositeClip);
 
   ret = (*pGC->ops->CopyPlane) (pSrc, pDst, pGC, srcx, srcy, w, h,
   box.x2 = maxX + 1 + pDrawable->x;
   box.y2 = maxY + 1 + pDrawable->y;
 
-  RegionInit(&reg, &box, 0);
+  RegionInitBoxes(&reg, &box, 1);
   RegionIntersect(&reg, &reg, pGC->pCompositeClip);
 
   (*pGC->ops->PolyPoint) (pDrawable, pGC, mode, npt, pts);
   box.x2 = maxX + 1 + pDrawable->x;
   box.y2 = maxY + 1 + pDrawable->y;
 
-  RegionInit(&reg, &box, 0);
+  RegionInitBoxes(&reg, &box, 1);
   RegionIntersect(&reg, &reg, pGC->pCompositeClip);
 
   (*pGC->ops->FillPolygon) (pDrawable, pGC, shape, mode, count, pts);
 
   GetTextBoundingRect(pDrawable, pGC->font, x, y, count, &box);
 
-  RegionInit(&reg, &box, 0);
+  RegionInitBoxes(&reg, &box, 1);
   RegionIntersect(&reg, &reg, pGC->pCompositeClip);
 
   ret = (*pGC->ops->PolyText8) (pDrawable, pGC, x, y, count, chars);
 
   GetTextBoundingRect(pDrawable, pGC->font, x, y, count, &box);
 
-  RegionInit(&reg, &box, 0);
+  RegionInitBoxes(&reg, &box, 1);
   RegionIntersect(&reg, &reg, pGC->pCompositeClip);
 
   ret = (*pGC->ops->PolyText16) (pDrawable, pGC, x, y, count, chars);
 
   GetTextBoundingRect(pDrawable, pGC->font, x, y, count, &box);
 
-  RegionInit(&reg, &box, 0);
+  RegionInitBoxes(&reg, &box, 1);
   RegionIntersect(&reg, &reg, pGC->pCompositeClip);
 
   (*pGC->ops->ImageText8) (pDrawable, pGC, x, y, count, chars);
 
   GetTextBoundingRect(pDrawable, pGC->font, x, y, count, &box);
 
-  RegionInit(&reg, &box, 0);
+  RegionInitBoxes(&reg, &box, 1);
   RegionIntersect(&reg, &reg, pGC->pCompositeClip);
 
   (*pGC->ops->ImageText16) (pDrawable, pGC, x, y, count, chars);
 
   GetTextBoundingRect(pDrawable, pGC->font, x, y, nglyph, &box);
 
-  RegionInit(&reg, &box, 0);
+  RegionInitBoxes(&reg, &box, 1);
   RegionIntersect(&reg, &reg, pGC->pCompositeClip);
 
   (*pGC->ops->ImageGlyphBlt) (pDrawable, pGC, x, y, nglyph, ppci, pglyphBase);
 
   GetTextBoundingRect(pDrawable, pGC->font, x, y, nglyph, &box);
 
-  RegionInit(&reg, &box, 0);
+  RegionInitBoxes(&reg, &box, 1);
   RegionIntersect(&reg, &reg, pGC->pCompositeClip);
 
   (*pGC->ops->PolyGlyphBlt) (pDrawable, pGC, x, y, nglyph, ppci, pglyphBase);
   box.x2 = box.x1 + w;
   box.y2 = box.y1 + h;
 
-  RegionInit(&reg, &box, 0);
+  RegionInitBoxes(&reg, &box, 1);
   RegionIntersect(&reg, &reg, pGC->pCompositeClip);
 
   (*pGC->ops->PushPixels) (pGC, pBitMap, pDrawable, w, h, x, y);