Trac’in as https://abcl.org/trac/ticket/475
I have found that I can "protect" a .abcl file from this bug, by using these commands:
unzip foo.abcl __loader__._ sed -i 's/(setq/(CL:SETQ/ig' __loader__._ zip -f foo.abcl __loader__._
This is not a proper fix, because it would corrupt any other place where the five-character sequence "(setq" happens to appear.
A proper fix would probably involve binding *PACKAGE* to a package in which none of the symbols that are in the content that is about to be written to __loader__._, other than keywords, are present or inherited.