+;;; FIXME: As far as I know, the CMU CL X86 codebase has never
+;;; supported access to the environment of the debugged function. It
+;;; would be really, really nice to make that work! (Until then,
+;;; non-NIL *AUTO-EVAL-IN-FRAME* seems to be useless, and as of
+;;; sbcl-0.6.10 it even seemed to be actively harmful, since the
+;;; debugger gets confused when trying to unwind the frames which
+;;; arise in SIGINT interrupts. So it's set to NIL.)
+(defvar *auto-eval-in-frame* nil