Singular segment initialization

Code/Seg/BlurredSegment/blurredsegmentproto.cpp

@@ -254,6 +254,11 @@ BlurredSegment *BlurredSegmentProto::endOfBirth ()
   {
     Pt2i llast = plist->frontPoint ();
     Pt2i rlast = plist->backPoint ();
+    if (llast.equals (rlast)) // Strange, should not be flat, rightok or leftok
+    {
+      plist = NULL;
+      return (NULL);
+    }
     int xmin = llast.x ();
     if (rlast.x () < llast.x ()) xmin = rlast.x ();
     int ymin = llast.y ();