PKCS7_sign_ex
p7 = PKCS7_sign_ex(NULL, NULL, other, in, flags, libctx, app_get0_propq());
return PKCS7_sign_ex(signcert, pkey, certs, data, flags, NULL, NULL);
PKCS7 *PKCS7_sign_ex(X509 *signcert, EVP_PKEY *pkey, STACK_OF(X509) *certs,