gnu: Add emacs-logos.

* gnu/packages/emacs-xyz.scm (emacs-logos): New variable.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/packages/emacs-xyz.scm

@@ -13197,6 +13197,42 @@ (define-public emacs-log4e
 you to deal with multiple log levels.")
     (license license:gpl3+)))
 
+(define-public emacs-logos
+  (package
+    (name "emacs-logos")
+    (version "0.3.1")
+    (source (origin
+              (method git-fetch)
+              (uri (git-reference
+                    (url "https://git.sr.ht/~protesilaos/logos")
+                    (commit version)))
+              (file-name (git-file-name name version))
+              (sha256
+               (base32
+                "1xhnhaxmjqdv0bbh22gj9ak83hha8d59q64b6aa4rynrgcyajk45"))))
+    (native-inputs (list texinfo))
+    (build-system emacs-build-system)
+    (arguments
+     (list
+      #:phases
+      #~(modify-phases %standard-phases
+          (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 "logos.info" (string-append #$output "/share/info")))))))
+    (home-page "https://protesilaos.com/emacs/logos")
+    (synopsis "Simple focus mode for Emacs")
+    (description "This package provides a simple focus mode which can be
+applied to any buffer for reading, writing, or even doing a presentation.  The
+buffer can be divided in pages using the @code{page-delimiter}, outline
+structure, or any other pattern.")
+    (license (list license:gpl3+
+                   license:fdl1.3+)))) ; GFDLv1.3+ for the manual
+
 (define-public emacs-gn-mode
   (package
     (name "emacs-gn-mode")