* module/rnrs/exceptions.scm (&guile): New condition type.
(guile-condition-converters): New variable.
(convert-guile-condition, default-guile-condition-converter,
set-guile-condition-converter!, guile-common-conditions,
guile-lexical-violation-converter, guile-syntax-violation-converter,
guile-assertion-violation-converter, guile-system-error-converter,
guile-undefined-violation-converter, guile-error-converter,
guile-implementation-restriction-converter): New procedures.
(with-exception-handler): Catch all exceptions, not just R6RS
exceptions. Convert native Guile exceptions to R6RS conditions,
preserving the original Guile exception information in the &guile
condition object.
(raise): If the condition includes a &guile condition, use 'throw' to
throw the original native guile exception instead of raising an R6RS
exception.
* test-suite/tests/r6rs-exceptions.test ("guile condition conversions"):
Add tests.
* module/rnrs/6/exceptions.scm: (guard0, guard): New syntax.
* module/rnrs/records/6/procedural.scm: (r6rs-raise-continuable): Can't
use `raise' here because it's exported by (rnrs exceptions); use plain
old `throw' instead.
* test-suite/Makefile.am: Add tests/r6rs-exceptions.test to SCM_TESTS.
* test-suite/tests/r6rs-exceptions.test: New file.
