Sorry if I have missed a previous thread about this problem.

I am running SLIME 2013-03-02 with SBCL-1.1.5 with :SB-THREADS on Mac OS X.

In the SLIME debugger (sldb) I attempt to find the definition of a function shown in a stack frame and it fails with the message:
   "No known definition for: MERGE-SHARED-LIBRARY-PATHNAME-TYPE (in COMMON-LISP-USER)"

That symbol is actually in my package QFFI.