This allows the directives to be used even if asdf is invoked by other means.
It looks like *debugger-hook* works just as well as sb-ext:*invoke-debugger-hook* for controlling application termination, so I this patch update the documentation to just mention *debugger-hook* which has the benefit of being portable CL.
A number of new interoperability functions and macros in utils.lisp which are used in dumper.lisp and in buildapp.lisp. A `ccl' field added to the `dumper' class. And some #+sbcl and #+ccl conditional forms in buildapp.lisp to correctly compile executables with ccl.