Index: layer.h
===================================================================
--- layer.h	(revision 14741)
+++ layer.h	(revision 14742)
@@ -266,7 +266,10 @@
 /* Calculate a hash of a bound layer (ingoring its name) */
 unsigned int pcb_layer_hash_bound(pcb_layer_t *ly);
 
+/* Calculate mirrored version of some (bound) layer properties */
+pcb_layer_type_t pcb_layer_mirror_type(pcb_layer_type_t lyt);
 
+
 /* Modify tree pointers in dst to point to src's; allocates trees for src if they are not yet allocated */
 void pcb_layer_link_trees(pcb_layer_t *dst, pcb_layer_t *src);