gnu: emacs-corfu: Generate info from README.org.

* gnu/packages/emacs-xyz.scm (emacs-corfu)[native-inputs]: Add texinfo.
[arguments]: Migrate to gexps, generate info from README.org.

gnu/packages/emacs-xyz.scm

@@ -3798,16 +3798,27 @@ (define-public emacs-corfu
         (base32 "1xqg796844wk6kvn3xw4bqlxn9ra6jlwk7rsc5gy4j77l0gwl441"))))
     (build-system emacs-build-system)
     (arguments
-     `(#:phases
-       (modify-phases %standard-phases
-         ;; Move the extensions source files to the top level, which is included
-         ;; in the EMACSLOADPATH.
-         (add-after 'unpack 'move-source-files
-           (lambda _
-             (let ((el-files (find-files "./extensions" ".*\\.el$")))
-               (for-each (lambda (f)
-                           (rename-file f (basename f)))
-                         el-files)))))))
+     (list
+      #:phases
+      #~(modify-phases %standard-phases
+          ;; Move the extensions source files to the top level, which is included
+          ;; in the EMACSLOADPATH.
+          (add-after 'unpack 'move-source-files
+            (lambda _
+              (let ((el-files (find-files "./extensions" ".*\\.el$")))
+                (for-each (lambda (f)
+                            (rename-file f (basename f)))
+                          el-files))))
+          (add-after 'install 'makeinfo
+            (lambda* (#:key outputs #:allow-other-keys)
+              (invoke "emacs"
+                      "--batch"
+                      "--eval=(require 'ox-texinfo)"
+                      "--eval=(find-file \"README.org\")"
+                      "--eval=(org-texinfo-export-to-info)")
+              (install-file "corfu.info"
+                            (string-append #$output "/share/info")))))))
+    (native-inputs (list texinfo))
     (propagated-inputs
      (list emacs-compat))
     (home-page "https://github.com/minad/corfu")