It can be installed (
for now), but there is a security issue with it if I remember correctly, something about it giving unlimited root access to the process launched with it...um... ah, here is a brief about it!
https://itsfoss.com/gksu-replacement-ubuntu/ wrote:
Brief: gksu is deprecated. It is removed from Debian, Ubuntu 18.04 and other newer Linux distribution version. You can achieve the gksu functionality with gvfs admin backend. Here’s how to do that.
I was slightly surprised to find it not installed by default so I went on to install it. And this is where my surprise turned into a shock.
When I tried using sudo apt install gksu, my system told me “Package ‘gksu’ has no installation candidate“.
Another fair article on this subject can be found
here, as well as a lot of other places. I've seen about 10 different ways to adapt to it suggested.
There are recommended ways and lazy but just as effective ways to deal with it. Max recommends one way, along the lines of that thinking though, you could just as easily open a run dialog (alt+F2 on most 'nixes) and type in 'sudo' and the name of the file manager in use (such as Caja, Nautilus, Thunar, etc), then browse to the livecode file and open it that way, or edit a file and create a menu entry (if not already existing) to do the same.
Another thing to note here is that if you are installing Lc for only you (which is what I believe 97% of people who aren't teachers or admins really should be using), then none of this matters since it installs it to your account and doesn't require admin priviledges.