The latest tag is many years old, and the latest upstream branch includes
important fixes such as displaying correctly the backtrace upon encountering
errors (see:
4b6e6cb81f).
* gnu/packages/emacs-xyz.scm (emacs-ert-runner): Update to the latest upstream
commit.
[origin]: Use GIT-FETCH instead of URL-FETCH to mitigate against GitHub's
dynamically generated tarballs.
This removes emacs-xyz.scm from the closure of (gnu packages base).
* gnu/packages/package-management.scm (emacs-nix-mode): Move back to...
* gnu/packages/emacs-xyz.scm (emacs-nix-mode): ... here. New variable.
* gnu/packages/emacs.scm: Move almost all packages from here...
* gnu/packages/emacs-xyz.scm: ...to this new module.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
* gnu/packages/ocaml.scm,
gnu/packages/package-management.scm,
gnu/packages/statistics.scm: Update module references.