Add new control GCRYCTL_GET_TAGLEN for use with gcry_cipher_info.
* src/gcrypt.h.in (GCRYCTL_GET_TAGLEN): New. * cipher/cipher.c (_gcry_cipher_info): Add GCRYCTL_GET_TAGLEN feature. * tests/basic.c (_check_gcm_cipher): Check that new feature. (_check_poly1305_cipher): Ditto. (check_ccm_cipher): Ditto. (do_check_ocb_cipher): Ditto. (check_ctr_cipher): Add negative test for new feature.
- Signed-off-by: Werner Koch <wk@gnupg.org>