Index: trunk/src/layer_grp.h
===================================================================
--- trunk/src/layer_grp.h	(revision 19748)
+++ trunk/src/layer_grp.h	(revision 19749)
@@ -259,11 +259,11 @@
 extern const pcb_dflgmap_t *pcb_dflgmap_first_bottom_noncopper;
 
 /* predefined common default map entries for building a stack */
-const pcb_dflgmap_t pcb_dflg_top_copper;
-const pcb_dflgmap_t pcb_dflg_int_copper;
-const pcb_dflgmap_t pcb_dflg_substrate;
-const pcb_dflgmap_t pcb_dflg_bot_copper;
-const pcb_dflgmap_t pcb_dflg_outline;
+extern const pcb_dflgmap_t pcb_dflg_top_copper;
+extern const pcb_dflgmap_t pcb_dflg_int_copper;
+extern const pcb_dflgmap_t pcb_dflg_substrate;
+extern const pcb_dflgmap_t pcb_dflg_bot_copper;
+extern const pcb_dflgmap_t pcb_dflg_outline;
 
 
 /* Overwrite an existing group from a default layer group map entry and create