[slime-devel] XREF for SBCL

The attached patch + new file hooks the PXREF to SBCL as well, sharing code with the Clisp backend.

To make usage a bit less tedious I hooked PXREF:XREF-FILE into swank-compile-file.

Clisp hasn't been tested after these changes, and neither has SBCL been subjected to much pounding, but "seems to work".

To make the pxref more useful it might make sense to save the collected db on exits and load on startup... Also, an xref-op for asdf would not come amiss. (Just noting these out loud in case someone has nothing to do over the weekend.)

Cheers,

-- Nikodemus Schemer: "Buddha is small, clean, and serious." Lispnik: "Buddha is big, has hairy armpits, and laughs."