gnu: Add emacs-cl-generic.

* gnu/packages/emacs.scm (emacs-cl-generic): New public variable.

gnu/packages/emacs.scm

@@ -7665,3 +7665,24 @@ (define-public emacs-pg
       (description
        "This package provides an Emacs Lisp interface for PostgreSQL.")
       (license license:gpl3+))))
+
+(define-public emacs-cl-generic
+  (package
+    (name "emacs-cl-generic")
+    (version "0.3")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append "https://elpa.gnu.org/packages/cl-generic-"
+                           version ".el"))
+       (sha256
+        (base32
+         "0vb338bhjpsnrf60qgxny4z5rjrnifahnrv9axd4shay89d894zq"))))
+    (build-system emacs-build-system)
+    (home-page "https://elpa.gnu.org/packages/seq.html")
+    (synopsis
+     "Forward @code{cl-generic} compatibility for Emacs before version 25")
+    (description "This package provides a subset of the features of the
+@code{cl-generic} package introduced in Emacs-25, for use on previous
+@code{emacsen}.")
+    (license license:gpl3+)))