sometimes the build would fail because of "missing" packages that
weren't actually missing (this only happened in ports that aren't
committed yet).
Rewrite the FASL placement code using the asdf-binary-locations
extension, which is already included in the cl-asdf port but needs
to be installed from ports when building for SBCL (which has its
own ASDF code). The binary-locations code generates paths unsuitable
for PLISTs, therefore it has been overridden with
lisp-specific-fasl-subdir.
Because of the new code, PLIST generation for cl-*-sbcl and cl-*-clisp
ports is now entirely automated.
All dependent cl-* ports are upgraded (obsolete code removed,
PORTREVISION bumped).
