Work-around built-in ~/common-lisp/ in search path?

[Robert Goldman]

Here's my issue:

1. I have a bunch of lisp libraries that I use on everyday things
installed in ~/common-lisp/.  One of the systems in there is an older,
modified version of fiveam that my company uses in many projects.

2. I have a project where we use libraries from quicklisp to make it
easier to handle dependencies.  For this project, I run a function that
resets the ASDF source-registry, and uses a special copy of quicklisp (a
copy that writes its systems in a different location).

3. I cannot build my system because the version of fiveam in
~/common-lisp/ shadows the version of fiveam from quicklisp, which I need.

4. I don't see any OBVIOUS way to tell ASDF to ignore my ~/common-lisp/
directory.  I can do the following:

  (setf asdf:*default-source-registries*
        (remove 'asdf/source-registry::default-user-source-registry
                asdf:*default-source-registries*))

but that seems really hard-core.  Would it be reasonable to make the
defaults a little easier to override?

Maybe something that's equivalent to --no-userinit and --no-sysinit when
starting lisp -- something that will remove the user-specific entries or
system-specific entries, respectively?

I don't believe I can simply wipe the defaults, because then I might
miss some SBCL libraries that come with the system default settings.

Cheers,
r