* src/gcrypt.h.in (enum gcry_kem_algos): Remove
GCRY_KEM_OPENPGP_X25519, GCRY_KEM_CMS_X25519_X963_SHA256, and
GCRY_KEM_CMS_X25519_HKDF_SHA256.
* cipher/kem.c (_gcry_kem_keypair, _gcry_kem_encap): Likewise.
(_gcry_kem_decap): Likewise.
* cipher/kem-ecc.c (algo_to_curve): Follow the removal.
(algo_to_seckey_len): Likewise.
(openpgp_kem_kdf, _gcry_openpgp_kem_encap): Remove.
(_gcry_openpgp_kem_decap, cms_kem_kdf): Remove.
(_gcry_cms_kem_encap, _gcry_cms_kem_decap): Remove.
* cipher/kem-ecc.h: Follow the removal.
* tests/t-kem.c (test_kem_openpgp_x25519) Remove.
(test_kem_cms_x25519): Remove.
(check_kem, main): Follow the change.