Function libsodium::crypto_stream_xsalsa20_xor

pub unsafe extern "C" fn crypto_stream_xsalsa20_xor(
    c: *mut c_uchar, 
    m: *const c_uchar, 
    mlen: c_ulonglong, 
    n: *const c_uchar, 
    k: *const c_uchar
) -> c_int