* build-aux/gitlab-ci.yml,
build-aux/pre-inst-env.in,
configure.ac,
test.sh,
tests/spec/Makefile.am,
tests/spec/check-spec: Add copyright notices and GPLv3+ license notice.
* guix.scm: Add a "special exception" permissive license notice.
* doc/syntax.txt: Add title, introduction, copyright notice, and a
simple all-permissive license.
* COPYING.CC0: New file.
* NEWS: Reformat and add CC0 license notice.
* README: Add CC0 license notice.
* Makefile.am: Add copyright notices and GPLv3+ license notice.
(EXTRA_DIST): Add COPYING.CC0.