size_t _goboringcrypto_EVP_AEAD_max_tag_len(const GO_EVP_AEAD*);
typedef struct GO_EVP_AEAD_CTX { char data[600]; } GO_EVP_AEAD_CTX;
void _goboringcrypto_EVP_AEAD_CTX_zero(GO_EVP_AEAD_CTX*);
int _goboringcrypto_EVP_AEAD_CTX_init(GO_EVP_AEAD_CTX*, const GO_EVP_AEAD*, const uint8_t*, size_t, size_t, GO_ENGINE*);
void _goboringcrypto_EVP_AEAD_CTX_cleanup(GO_EVP_AEAD_CTX*);

		}
	default:
		// Fall back to standard library for GCM with non-standard key size.
		return cipher.NewGCMWithNonceSize(&noGCM{c}, gcmStandardNonceSize)
	}

	g := &aesGCM{aead: aead}
	if C._goboringcrypto_EVP_AEAD_CTX_init(&g.ctx, aead, (*C.uint8_t)(unsafe.Pointer(&c.key[0])), C.size_t(len(c.key)), C.GO_EVP_AEAD_DEFAULT_TAG_LENGTH, nil) == 0 {
		return nil, fail("EVP_AEAD_CTX_init")
	}