SCI: fix for heap corruption during lsl3 ending

engines/sci/graphics/screen.cpp

@@ -286,11 +286,15 @@ void GfxScreen::putPixelOnDisplay(int x, int y, byte color) {
  * with flood fill, due to small difference in the Bresenham logic.
  */
 void GfxScreen::drawLine(Common::Point startPoint, Common::Point endPoint, byte color, byte priority, byte control) {
-	int16 left = startPoint.x;
-	int16 top = startPoint.y;
-	int16 right = endPoint.x;
-	int16 bottom = endPoint.y;
-
+    int16 maxWidth = _width - 1;
+    int16 maxHeight = _height - 1;
+    // we need to clip values here, lsl3 room 620 background picture draws a line from 0, 199 t 320, 199
+    //  otherwise we would get heap corruption.
+	int16 left = CLIP<int16>(startPoint.x, 0, maxWidth);
+	int16 top = CLIP<int16>(startPoint.y, 0, maxHeight);
+	int16 right = CLIP<int16>(endPoint.x, 0, maxWidth);
+	int16 bottom = CLIP<int16>(endPoint.y, 0, maxHeight);
+
 	//set_drawing_flag
 	byte drawMask = getDrawingMask(color, priority, control);