Replace use of variable-length-arrays.

Replace use of variable-length-arrays.

* common/t-iobuf.c (main): Replace variable-length-array.
* g10/gpgcompose.c (mksubpkt_callback): Ditto.
(encrypted): Ditto.
* g10/t-stutter.c (log_hexdump): Ditto.
(oracle_test): Ditto.
* g10/tofu.c (get_policy): Ditto.  Use "%zu" for size_t.
* scd/app-openpgp.c (ecc_writekey): Replace variable-length-array.
Check for zero length OID_LEN.

Signed-off-by: Werner Koch <wk@gnupg.org>
(cherry picked from commit 6b84ecbf312d98ac8cce9fe5facdc815bc742fa1)

Gbp-Pq: Name 0017-Replace-use-of-variable-length-arrays.patch