pkcs11_add_provider
count = pkcs11_add_provider(canonical_provider, pin, &keys, &comments);
nkeys = pkcs11_add_provider(pkcs11provider, identity_passphrase,
nkeys = pkcs11_add_provider(pkcs11provider, NULL, &keys, &comments);
if ((nkeys = pkcs11_add_provider(name, pin, &keys, &labels)) > 0) {
int pkcs11_add_provider(char *, char *, struct sshkey ***, char ***);
(nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,