Note: the Common Lisp backend of Clue is broken and unlikely to be fixed. See Vacietis for a working and supported C to Common Lisp compiler.
Homepage: http://cluecc.sourceforge.net/
License: BSD
cluecc
Clue is an ANSI C programming language compiler that targets several languages, including Common Lisp. It supports the entire C language, including pointer arithmetic, and can be used to run arbitrary pure-C programs.