* cipher/dilithium-dep.c (crypto_sign_keypair_internal): New.
(crypto_sign_signature) [DILITHIUM_INTERNAL_API_ONLY]: Don't define.
(crypto_sign) [DILITHIUM_INTERNAL_API_ONLY]: Don't define.
(crypto_sign_verify) [DILITHIUM_INTERNAL_API_ONLY]: Don't define.
(crypto_sign_open) [DILITHIUM_INTERNAL_API_ONLY]: Don't define.
* cipher/dilithium.c: Define DILITHIUM_INTERNAL_API_ONLY for use
within libgcrypt.