In case this helps, I launch ABCL using this script, which I call abcl.sh:
#!/bin/bash exec rlwrap java -classpath $HOME/sw/jna-4.1.0.jar:/usr/local/abcl-bin-1.4.0/abcl.jar:/usr/local/asm-5.2/lib/all/asm-all-5.2.jar org.armedbear.lisp.Main "$@"
jna lets me use CFFI (if I remember correctly), asm lets me use #'disassemble, rlwrap gives me readline support
However, I suspect that you're trying to get your ASDF system to load in other people's installations, without requiring them to use a script like the above. In that case, the above is useless.
---- What if you just place your first snippet into its own file, say "load-jna.lisp". List that as the first file in your ASDF system. When subsequent files load, they will find JNA already in place. Might that work?
Vibhu