* cipher/cipher-gcm.c (_gcry_cipher_gcm_setiv_zero): New.
(_gcry_cipher_gcm_encrypt, _gcry_cipher_gcm_decrypt)
(_gcry_cipher_gcm_authenticate): Use _gcry_cipher_gcm_setiv_zero.
* cipher/cipher-internal.h (struct gcry_cipher_handle): Add aead field.
* cipher/cipher.c (_gcry_cipher_setiv): Check calling setiv to reject
direct invocation in FIPS mode.
(_gcry_cipher_setup_geniv, _gcry_cipher_geniv): New.
* doc/gcrypt.texi: Add explanation for two new functions.
* src/gcrypt-int.h (_gcry_cipher_setup_geniv, _gcry_cipher_geniv): New.
* src/gcrypt.h.in (enum gcry_cipher_geniv_methods): New.
(gcry_cipher_setup_geniv, gcry_cipher_geniv): New.
* src/libgcrypt.def (gcry_cipher_setup_geniv, gcry_cipher_geniv): Add.
* src/libgcrypt.vers: Likewise.
* src/visibility.c (gcry_cipher_setup_geniv, gcry_cipher_geniv): Add.
* src/visibility.h: Likewise.