SBCL signals "constant is being redefined " errors for +ffi-types+ and +ffi-styles+ in src/ffi-cffi.lisp, because the values of the constants are lists.
SBCL documentation explains the problem: http://www.sbcl.org/manual/Defining-Constants.html.
Ilya
Are you getting this because you are reloading src/ffi-cffi into your lisp?
The problem happens when ASDF compiles and then loads the file, because SBCL evaluates DEFCONSTANTs in both compile time and load time.
Yes, this happens to me on SBCL. I've been lazy and keep ignoring this.
Will fix this.