specl: remove reference to deleted specl.version module.

* src/specl.lua: Remove `require "spec.version"`.
(M._VERSION): Remove.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
sanity: allow OptionParser in optparse error messages.

* build-aux/sanity.mk: Update from slingshot.
* build-aux/sanity-cfg.mk (sc_error_message_uppercase): Exclude
specl/optparse.lua from check.
(EXTRA_DIST): Add build-aux/sanity-cfg.mk.

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