Revert "maint: post-release administrivia."

This reverts commit 9fcdd06a1f88d6db0ab344b0de4dda314ff8eb8c.
maint: support external_dependencies with mkrockspecs.

* build-aux/mkrockspecs: Support ordering of external_dependencies.
Add quote marks around various paths in case of whitespace after
variable expansion.
(configure_flags): Set defaults to respect external_dependencies
entries.
* rockspec.conf (external_dependencies): Required for a correct
build.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
maint: Move distribution rules into release.mk.

* Makefile.am: Move distribution rules from here...
* build-aux/release.mk: ...to here.
* build-aux/rockspecs.mk (EXTRA_DIST): Add mkrockspecs script,
and rockspec_conf.
(smc_rockspec): git rockspec is always revision 1!

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
configury: rockspecs depend on lyaml.

* Makefile.am: Make sure lyaml is built before calling mkrockspecs.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
maint: remove unused lyaml-rockspec.lua.

* lyaml-rockspec.lua: Remove.  No longer used.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
travis: adjust for slingshot upgrades.

* .travis.yml: Be as verbose as possible.
Don't try to bootstrap the release branch.
Adjust luarcoks-config.lua path.
Remove lua-stdlib install; slingshot mkrockspecs works without it.
Pass LUAROCKS to make correctly.
(LUAROCKS_CONFIG): Set correctly.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
Release version 3

* NEWS: Record release date.
maint: post-release administrivia.

* configure.ac (AC_INIT): Bump to release 4.
* NEWS: Add header line for next release.
* .prev-version: Record previous version.
* ./Makefile.am (old_NEWS_hash): Auto-update.

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