zile: when resetting a path following "//", start back at root.

* lib/zile/file.lua (canonicalize_filename): When encountering
a double / in a path, and resetting to root, don't forget to
mark the root directory with an initial "" in ncomp.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
zlisp: save-buffers-kill-emacs saves without prompting with ARG.

* lib/zile/file.lua (save_some_buffers): New `noask` parameter.
* lib/zmacs/zlisp/file.zl (save-buffers-kill-emacs): Accept an
optional prefix arg, and pass to `save_some_buffers`.
* NEWS: Update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
zile: fix assert in switch_to_buffer, for after set-buffer.

If a ZLisp program changes the buffer_stack with `set-buffer` or
otherwise, and `switch_to_buffer` is called before reaching the
command read loop, handle the stack correctly.
* lib/zile/buffer.lua (switch_to_buffer): Don't fail the initial
assert if the current window still holds the buffer on the bottom
of the stack.
If the buffer for the current window is successfully changed,
then switch the buffer on the bottom of the stack too so that
when the stack unwinds, the buffer doesn't change back again.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
zlisp: support optional insert argument to `where-is`.

* lib/zmacs/zlisp/bind.zl (where-is): Support optional insert
parameter.  Use the some output format as Emacs when insert is
non-nil.
* NEWS: Update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
specl: start adding specl specifications for zlisp.

Start with the previously untested (previously untestable!)
`where-is` command.
* configure.ac (AC_PATH_PROG): Probe for a specl command.
* bootstrap.conf (buildreq): Add specl.  Note, we need bugfixes
from an unreleased Specl at the moment.
(slingshot_files): Add bulid-aux/specl.mk.
* lib/zmacs/specs/spec_helper.lua: New file. Matchers and helpers
for running zmacs and checking buffer and minibuf results.
* lib/zmacs/specs/zlisp_bind_spec.yaml (where-is): Specify
behaviour of `where-is` command.
* lib/zmacs/specs/specs.mk: New file. Declare specl spec files.
* local.mk: Include it.
* travis.yml.in (script): Check specs.
* .travis.yml: Regenerate.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>