build: Require latest released libraries
* agent/protect.c (OCB_MODE_SUPPORTED): Remove macro. (do_encryption): Always support OCB. (do_decryption): Ditto. (agent_unprotect): Ditto. * dirmngr/server.c (is_tor_running): Unconditionally build this.
Although not technically required, it is easier to require them to
avoid bug reports due to too old library versions.
- Signed-off-by: Werner Koch <wk@gnupg.org>