website: Add post about GSoC.

* website/posts/join-gnu-guix-for-gsoc-2017.md: New file.
* website/haunt.scm: Add COMMONMARK-READER.
* website/www.scm (sxml->string*)[sxml->strings]: Automatically wrap
lists in <div>.

website/haunt.scm

@@ -1,6 +1,6 @@
 ;;; GuixSD website --- GNU's advanced distro website
 ;;; Copyright © 2015 Mathieu Lirzin <mthl@gnu.org>
-;;; Copyright © 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GuixSD website.
 ;;;
@@ -21,6 +21,7 @@
 
 (use-modules (haunt site)
              (haunt reader)
+             (haunt reader commonmark)
              (haunt page)
              (haunt html)
              (haunt utils)
@@ -70,7 +71,7 @@
       #:default-metadata
       '((author . "GuixSD Contributors")
         (email  . "guix-devel@gnu.org"))
-      #:readers (list sxml-reader html-reader)
+      #:readers (list sxml-reader html-reader commonmark-reader)
       #:builders
       `(,(lambda (site posts)                     ;the main page
            (with-url-parameters

website/posts/join-gnu-guix-for-gsoc-2017.md

@@ -0,0 +1,51 @@
+title: Join GNU Guix for GSoC
+date: 2017-03-09 14:00
+author: Ludovic Courtès
+slug: join-gnu-guix-for-gsoc-2017
+tags: gsoc
+---
+As in
+[previous](https://www.gnu.org/software/guix/news/gnu-guix-welcomes-four-students-for-gsoc.html)
+[years](https://www.gnu.org/software/guix/news/gnu-guix-welcomes-three-students-for-gsoc.html),
+Guix participates in the [Google Summer of
+Code](https://summerofcode.withgoogle.com/) (GSoC), under the aegis of the [GNU
+Project](https://www.gnu.org/software/soc-projects/ideas-2017.html).
+
+We have collected project ideas for [Guix,
+GuixSD](https://libreplanet.org/wiki/Group:Guix/GSoC-2017), as well as
+[the GNU
+Shepherd](https://libreplanet.org/wiki/Group:Guix/GSoC-2017#Project_ideas_for_the_GNU_Shepherd),
+covering a range of topics.  If you are passionate about computing
+freedom, Scheme, functional programming, or operating system
+development, check out the proposed projects.  The list is far from
+exhaustive, so feel free to bring your own!
+
+You can get in touch with us on [the mailing
+lists](https://www.gnu.org/software/guix/about/#contact) and on the
+`#guix` channel on the Freenode IRC network.
+
+If you are an [eligible
+student](https://developers.google.com/open-source/gsoc/faq#can_i_participate_in_gsoc_as_both_a_mentor_and_a_student),
+make sure to apply [by April
+3rd](https://developers.google.com/open-source/gsoc/timeline).
+
+#### About GNU Guix
+
+[GNU Guix](https://www.gnu.org/software/guix) is a transactional package
+manager for the GNU system.  The Guix System Distribution or GuixSD is
+an advanced distribution of the GNU system that relies on GNU Guix and
+[respects the user's
+freedom](https://www.gnu.org/distros/free-system-distribution-guidelines.html).
+
+In addition to standard package management features, Guix supports
+transactional upgrades and roll-backs, unprivileged package management,
+per-user profiles, and garbage collection.  Guix uses low-level
+mechanisms from the Nix package manager, except that packages are
+defined as native [Guile](https://www.gnu.org/software/guile) modules,
+using extensions to the [Scheme](http://schemers.org) language.  GuixSD
+offers a declarative approach to operating system configuration
+management, and is highly customizable and hackable.
+
+GuixSD can be used on an i686 or x86_64 machine.  It is also possible to
+use Guix on top of an already installed GNU/Linux system, including on
+mips64el and armv7.

website/www.scm

@@ -1,5 +1,5 @@
 ;;; GuixSD website --- GNU's advanced distro website
-;;; Copyright © 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2015 Mathieu Lirzin <mthl@openmailbox.org>
 ;;; Initially written by Luis Felipe López Acevedo <felipe.lopez@openmailbox.org>
 ;;; who waives all copyright interest on this file.
@@ -59,7 +59,9 @@ string."
       (((? symbol?) body ...)
        (append-map sxml->strings body))
       ((? string?)
-       (list tree))))
+       (list tree))
+      ((lst ...)
+       (sxml->strings `(div ,@lst)))))
 
   (string-concatenate (sxml->strings tree)))