gpgscm: Introduce macro for the vector length.
* tests/gpgscm/scheme.c (vector_length): New macro. (get_vector_object): Use the new macro. (oblist_add_by_name): Likewise. (oblist_find_by_name): Likewise. (oblist_all_symbols): Likewise. (mk_vector): Likewise. (mark): Likewise. (new_slot_spec_in_env): Likewise. (find_slot_spec_in_env): Likewise. (opexe_2): Likewise. (opexe_5): Likewise.
Introducing an abstraction reduces the coupling between code using
vectors and the implementation of vectors.
- Signed-off-by: Justus Winter <justus@g10code.com>