Emacs: Add package spdx.

init.d/programming/common.el

@@ -245,5 +245,12 @@ year if mode is derived from prog-mode."
   :straight (:type built-in)
   :hook (diff-mode . (lambda () (setq-local my/reformat-save nil))))
 
+;; Insert SPDX license identifiers.
+(use-package spdx
+  :custom((spdx-copyright-holder 'auto)
+          (spdx-project-detection 'auto))
+  :bind (:map prog-mode-map
+              ("C-c i l" . spdx-insert-spdx)))
+
 (provide 'programming/common)
 ;;; common.el ends here