"Symbol’s value as variable is void:"

[davidpiano]

• What did you do?
  I installed org-utf-to-xetex on my Termux system (a Linux-on-Android installation that uses modified Debian sources and a modified but pretty complete version of TexLive 2020). I'm running Emacs 26.3 on the console terminal without starting any graphical interface, because the GUI system is very cumbersome on this little screen, but I could temporarily run the GUI for troubleshooting if needed. Org-mode's LaTeX export to PDF was working before I installed org-utf-to-xetex, without the capability for arbitrary Unicode characters of course.

I created ~/src/org-utf-to-xetex as a clone of this repository, following the written installation directions as much as possible though I decided to keep my .sty file local and not upload it since all my other config files are local. (I thought it was odd that I was directed to make a copy of my system's texmf.cnf file and then not move either the original or the copy; is that just a general precaution in case I change the .cnf file myself, or does org-utf-to-xetex later modify it?)

Not having a dedicated LaTeX editor installed, I created "new.org" which, in its simple original form without Unicode content, was successful.

• What did you expect to happen

I expected that exporting a Unicode-containing file, either new.org or the sample file Emoticons.org, would create a PDF

• What happened instead?

An error occurred immediately: Symbol’s value as variable is void: showing the first emoticon in the list as being the problem.

• Did you review issue tracker to see if this bug is already
  reported or resolved?

None of the other issues seemed related.

• Did you review the README about how this feature works?

Yes, though the README is not very specific or detailed about installation or troubleshooting.