Index: layer_grp.h
===================================================================
--- layer_grp.h	(revision 28233)
+++ layer_grp.h	(revision 28234)
@@ -260,7 +260,9 @@
 	pcb_layer_type_t lyt;
 	const char *purpose;
 	pcb_layer_combining_t comb;
-	int force_end;
+	enum { /* bitfield */
+		PCB_DFLGMAP_FORCE_END = 1
+	} flags;
 } pcb_dflgmap_t;
 
 extern const pcb_dflgmap_t pcb_dflgmap[]; /* the whole map, without doc layers */