* module/system/vm/traps.scm (new-disabled-trap): Don't manipulate the
VM trace level in the enable and disable handlers. Unfortunately, this
makes traps not work unless you enable hooks, but given that
vm_dispatch_hook has to set trace-level to 0, there needs to be an
object with a broader view of what traps are enabled. That object is
the hook state.
* module/system/vm/trap-state.scm (trap-state->trace-level): New
procedure.
(with-default-trap-handler): Add an optional trap-state argument. Now
makes sure that the vm-trace-level is set appropriately during the
execution of the thunk, allowing for breakpoints from recursive
prompts.
* module/system/vm/traps.scm: New module, implements higher-level traps
based on the VM hooks. Inspired by (ice-9 debugging traps). Instead of
the ice-9's variety, these traps have a procedural interface instead
of a GOOPS interface.
* module/Makefile.am: Add the new module.
