Function nginx::PKCS7_sign_add_signer

pub unsafe extern "C" fn PKCS7_sign_add_signer(
    p7: *mut PKCS7, 
    signcert: *mut X509, 
    pkey: *mut EVP_PKEY, 
    md: *const EVP_MD, 
    flags: c_int
) -> *mut PKCS7_SIGNER_INFO