Also works for me on an older system, Fedora 32.  Did not test on older Ubuntu 16 or Debian-32 bit 9.1 but even if it has problems there, it is more important to keep it updated for newer systems.  Older systems can just back out the 2 file / 2 line changes -- especially since makeappimage only needs to be built once and saved somewhere so as not to be deleted.

This will get checked into GIT soon.  Thanks Andrew -- you are really getting a workout these days!