use "configure -cursor {}" instead of "configure -cursor arrow" to switch back mouse cursor to default when exiting graph

src/callback.c

@@ -49,7 +49,7 @@ static int waves_selected(int event, KeySym key, int state, int button)
     }
   }
   if(!is_inside) {
-    tclvareval(xctx->top_path, ".drw configure -cursor arrow" , NULL);
+    tclvareval(xctx->top_path, ".drw configure -cursor {}" , NULL);
     if(xctx->graph_flags & 64) {
       tcleval("graph_show_measure stop");
     }

src/spice_netlist.c

@@ -778,7 +778,7 @@ void int_hash_free(Int_hashtable *hashtable)
       int_hash_free_entry( table[i] );
       table[i] = NULL;
     }
-    if(hashtable->table) my_free(1575, &(hashtable->table));
+    my_free(1575, &(hashtable->table));
     hashtable->size = 0;
   }
 }