changed RTree struct names: update diglib header

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@46940 15284696-431f-4ddb-bdfa-cd5b030d7da7

include/vect/dig_externs.h

@@ -218,7 +218,7 @@ int dig_Rd_spidx(struct gvfile *, struct Plus_head *);
 
 int dig_dump_spidx(FILE *, const struct Plus_head *);
 
-int rtree_search(struct RTree *, struct Rect *, SearchHitCallback ,
+int rtree_search(struct RTree *, struct RTree_Rect *, SearchHitCallback ,
 		void *, struct Plus_head *);
 
 /* struct_alloc.c */