use default_tag

Author: pelletjl

hinges.scad

@@ -387,16 +387,7 @@ module knuckle_hinge(length, segs, offset, inner=false, arm_height=0, arm_angle=
         union(){}
     }
   }
-  module in_place_clearance_tag() {
-      // don't set the tag if it's already set for backward compatibility
-      if(in_place != false && knuckle_clearance && $tag == "") {
-          tag("keep")
-              children();
-      } else {
-          children();
-      }
-  }
-  in_place_clearance_tag()
+  default_tag("keep", do_tag=in_place != false && knuckle_clearance)
   attachable(anchor,spin,orient,
              size=[length,
                    arm_height+offset/tan(arm_angle)+knuckle_diam/2+knuckle_diam/2/sin(arm_angle),