Readynas as VM and build-essential

once a long time ago, someone here recommended for me to use a VM for building stuff for Readynas and I actually had created a VM with build-essential and everything in there so that I could build stuff on the VM and test it before bringing any binary over to my actual unit.  But I lost that VM image long time ago....

I can even vaguely recall someone here helping me use a VM to build some stuff I needed, but I just can't remember the details now.  So...maybe grasping at straws, just trying to see if there is any way under the sun to get build-essential.

I have thought about also just making a jessie VM and try to build stuff there,  In some cases that might work but not always where readynas has custom libraries of some kind that I would need to bind to, such as in particular libc appears to be.  I could certainly try to build a new version of Python3 on a jessie VM and see if it works. ....it's a stretch.  That's the main thing I need now for one particular purpose that would get my readynas back to the working order it was in before I did a factory reset.

Otherwise I've pretty much decided it can still function great as a backup serve and even as my primary SMB file server and it can even do plex streaming still, but still dependent on a secondary machine to run some services which I use to be able to run on this, but can't now.  The only solution without build-essential is get a new NAS..but honestly I don't really want to do that right now, just because I can't decide which hardware I would get and I feel my readynas is still quite good hardware so I want to keep using it.  Just wish I could build the odd thing I need to build for it, in this case Python 3.5+