Implementation and test cases for the R6RS (rnrs record syntactic) library.
* module/Makefile.am: Add rnrs/6/hashtables.scm to RNRS_SOURCES.
* module/rnrs/6/hashtables.scm: New file.
* module/rnrs/records/6/inspection.scm: (record-type-generative?) Record
types are generative iff they have no uid, not vice-versa.
* module/rnrs/records/6/syntactic.scm: Finish `define-record-type'
implementation; add `record-type-descriptor' and
`record-constructor-descriptor' forms.
* test-suite/Makefile.am: Add tests/r6rs-records-syntactic.test to
SCM_TESTS.
* test-suite/tests/r6rs-records-inspection.test: Update tests for
`record-type-generative?' to reflect corrected behavior.
* test-suite/tests/r6rs-records-syntactic.test: New file.