Index: obj_arc.h
===================================================================
--- obj_arc.h	(revision 29715)
+++ obj_arc.h	(revision 29716)
@@ -64,7 +64,7 @@
 void pcb_arc_bbox(pcb_arc_t *Arc);
 void pcb_arc_rotate90(pcb_arc_t *Arc, pcb_coord_t X, pcb_coord_t Y, unsigned Number);
 void pcb_arc_rotate(pcb_layer_t *layer, pcb_arc_t *arc, pcb_coord_t X, pcb_coord_t Y, double cosa, double sina, pcb_angle_t angle);
-void pcb_arc_mirror(pcb_layer_t *layer, pcb_arc_t *arc, pcb_coord_t y_offs);
+void pcb_arc_mirror(pcb_layer_t *layer, pcb_arc_t *arc, pcb_coord_t y_offs, pcb_bool undoable);
 void pcb_arc_flip_side(pcb_layer_t *layer, pcb_arc_t *arc);
 void pcb_arc_scale(pcb_arc_t *arc, double sx, double sy, double sth);
 pcb_box_t pcb_arc_mini_bbox(const pcb_arc_t *arc);