configury: Makefile.am improvements.

* Makefile.am (dist_bin_SCRIPTS, dist_lua_DATA): Declare these
here, so that multiple fragments can each add additional files.
(EXTRA_DIST): Don't force distribution of README.md.
* local.mk (EXTRA_DIST): Add README.md.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
configury: remove Automake foreign requirement.

The only thing forcing us to use the hobbled "foreign" mode of
Automake is lack of COPYING and README files.  Adding them has
the added benefit of distributing a standard README file in
releases, but keeping README.md in the repository, which looks
nicer on github.
* COPYING: New file. Catch all license for files that don't have
their own explicit terms.
* bootstrap.conf (slingshot_force_readme): Link to README.md.
* configure.ac (AM_INIT_AUTOMAKE): Remove foreign.
(AX_PROG_LUA): Quote arguments correctly.
* .gitignore: Add COPYING and README.
* NEWS: Update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
README: update and expand.

* README.md (Installation): Document the `bootstrap.slingshot`
method, as well as "pick and choose" alternative.
(ax_with_prog.m4, mail): Remove.  These files are no longer part
of Slingshot.
* AUTHORS: Update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
configury: support non-autotools LuaRocks installation.

* build-aux/mkrockspecs.in: Add a Bourne shell preamble to make
a PATH search for suitable Lua binary and re-execute.
Support new --module-dir command-line option to specify a tree
of `.lua` files for installation, in preference to a full auto-
tools build.
Collect and correctly quote a LuaRocks `build.modules` table in
the generated rockspec when --module-dir is passed.
Also, await rockspec configuration on standard input when new
positional parameter for FILE is '-'.
* specs/package_spec.yaml: Remove dummy spec file.
* specs/mkrockspecs_spec.yaml: Verify behaviour of new functions
in mkrockspecs.
* specs/specs.mk (specl_SPECS): Adjust.
* build-aux/mkrockspecs.mk ($(package_rockspec)): Support optional
mkrockspecs_args for user arguments to mkrockspecs script.
* NEWS: Update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
bootstrap: diagnose missing slingshot_files settings.

* bootstrap.slingshot (slingshot_files): Add dummy setting with
doc-comment.
(slingshot_copy_files): Check slingshot_files is set.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
bootstrap: don't overwrite user settings in bootstrap.slingshot.

* bootstrap.slingshot (slingshot_files, slingshot_path)
(slingshot_url): Don't blindly set to empty, in case this file
is sourced *after* user settings.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
mkrockspecs: put source in src directory.

* build-aux/mkrockspecs.in: Move from here...
* src/mkrockspecs.in: ...to here.
* configure.ac (AC_CONFIG_FILES): Adjust.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
configury: bump release version to 3.

* configure.ac (AC_INIT): Bump release version to 3.

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