Hi,

Changes in this patch:

  * Remove enable-frame-unwinder!, disable-frame-unwinder!

  * set-frame-unwinder-enabled! takes frame unwinder object only, not a
    name

  * Removed priority; instead, first the unwinders for the current
    objfile are run, then the ones from the current progspace, then the
    global ones, but in an unspecified order within each locus

  * Renamed "scope" to "locus"

  * Names required to be unique only within locus

  * s/ephemeral frame/pending frame/

  * Documentation updates

  * make-unwind-info takes a frame-id object; added a make-frame-id
    constructor.

  * There's no recursion check in scm-frame-unwinder.c; instead the
    check in frame_unwind_is_unwinding is sufficient.

  * I kept the #:enabled init keyword to make-frame-unwinder, as it
    matches what frame filters do, as well as python filters/unwinders.
    Let me know if that was an error.

  * Removed dead "has-active-frame-unwinders?"

  * Fixed docstring on "all-frame-unwinders"

  * (prune-frame-unwinders!) doesn't cons if all unwinders are valid
    (i.e. their loci haven't gone away), and fix prune-frame-unwinders!
    docstring.

  * Renamed unregister-frame-unwinder! to remove-frame-unwinder!, as
    requested.

  * Fixed test coding style

  * Fixed some trailing .* in pattern

  * Test unwind before and after enabling unwinder

Still to do:

  * Make the test architecture-independent if possible

There were a couple of questions on the review from v4 of this patch
that I address specifically in the thread for v4 and don't mention
above.

WDYT? :)

Andy