CLISP - Integrate the SICL compiler into CLISP

This project aims to incorporate components from Robert Strandh’s SICL compiler called Cleavir into CLISP. Adding Cleavir would open up the possibility of adding an array of compiler optimizations, including flow sensitive ones. This new compiler middle-end is intended to transparently hook up to the existing CLISP front-end and byte-code backend. Overall, the expected end result is to get much faster compiled Lisp code from CLISP.