fix dig_spidx_add_line/area/isle() prototypes - see https://trac.osgeo.org/grass/changeset/52017

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@52018 15284696-431f-4ddb-bdfa-cd5b030d7da7

include/vect/dig_externs.h

@@ -193,9 +193,9 @@ void dig_spidx_free_isles(struct Plus_head *);
 void dig_spidx_free(struct Plus_head *);
 
 int dig_spidx_add_node(struct Plus_head *, int, double, double, double);
-int dig_spidx_add_line(struct Plus_head *, int, struct bound_box *);
-int dig_spidx_add_area(struct Plus_head *, int, struct bound_box *);
-int dig_spidx_add_isle(struct Plus_head *, int, struct bound_box *);
+int dig_spidx_add_line(struct Plus_head *, int, const struct bound_box *);
+int dig_spidx_add_area(struct Plus_head *, int, const struct bound_box *);
+int dig_spidx_add_isle(struct Plus_head *, int, const struct bound_box *);
 
 int dig_spidx_del_node(struct Plus_head *, int);
 int dig_spidx_del_line(struct Plus_head *, int, double, double, double);