Specifically:
- make predicate symbols and variables be original (and,
in the former case, have srclocs)
- remove the originality in the quoted syntax constants
that the expansion introduces
I think there is probably something better that should be done
with those introduced syntax constants, possibly relacing
them with #f, or possibly replacing them with source location
lists, but I'm not sure how they are used, so I've just left
them in there.
(Also, very minor Rackety in check syntax)
original commit: bf95ee10523daabea4925073ff035bf57ecad59f
6c9cb53757