* module/ice-9/getopt-long.scm (fatal-error): New helper. For errors
that come from the user -- i.e., not the grammar -- we will handle our
own error printing and call `exit' rather than relying on the root
catch handler. This is more friendly to the user than a Scheme
backtrace.
(parse-option-spec, process-options, getopt-long): Call `fatal-error'
as appropriate.
* test-suite/tests/getopt-long.test (pass-if-fatal-exception): New
helper, checks that a certain key was thrown to, and that suitable
output has been printed on an error port.
(deferr): Change to expect a 'quit key instead of 'misc-error. Update
exceptions to not match the beginning of the string, as that will be
the program name. Update tests to use pass-if-fatal-exception.
exception:option-does-not-support-arg,
exception:option-must-be-specified,
exception:option-must-have-arg, exception:not-enough-args): New vars.
("option-ref", "required", "specified no value, given anyway",
"specified arg required"): New top-level sections.
