Comment 11 for bug 1230368

As for the refactoring, it's simply renaming defsystem.lisp to parse-defsystem.lisp, to avoid the naming conflict between asdf/defsystem, as defined in asdf.asd and asdf/defsystem.lisp, now renamed asdf/parse-defsystem.lisp.

I also reordered things in the Makefile so subfiles are hopefully concatenated in the same order as in with asdf's monolithic-concatenate-source-op.