JNOS2 and Ubuntu Virtual Box

I'm running Ubuntu 18.04.1 LTS in an Oracle Virtualbox with a bridged network adapter on a Windows 10 laptop. I've got my Yaesu FT-857D and Signalink usb connections shared with the VM.  I'm thinking I need to use Direwolf.  However my Kenwood TH-D74a has a built in KISS TNC and was super easy to access in Linux.

To get JNOS2 to work, I thought I'd be able to just follow the instructions listed on the webpages.  Unfortunately this did not work for me.

When I downloaded and extracted the tar file and tried to run the installer, a message saying the file or directory doesn't exist.   This seems to indicate that prerequisite libraries aren't installed.  Eventually I discovered these needed to be installed:

sudo apt-get install libncurses5-dev
sudo apt-get install libssl-dev

I then received messages like in this thread: http://lists.tapr.org/pipermail/nos-bbs_lists.tapr.org/2018-July/005312.html

To resolve this, I downloaded this:

wget https://www.langelaar.net/jnos2/archive/news/tun_sp2l.c
cp tun_sp2l.c   <src directory>/tun.c

Running the make command was finally successful.  The JNOS installer ran successful.